USING GEOVIS AND LCCS MANUAL

Compiled by: Craig von Hagen

Supervised by: Antonio Di Gregorio

TABLE OF CONTENTS

1. WHAT IS GEOVIS?........................................................................................................ 3 2. LCCS ................................................................................................................................. 4 2.1. Making a legend ............................................................................................................. 4 2.2. Viewing the Legend ....................................................................................................... 6 2.3. Save and export the legend............................................................................................. 7 3. GEOVIS ............................................................................................................................ 9 3.1. Help Functions ............................................................................................................. 10 3.2. Main Toolbar................................................................................................................ 11 3.3. Project Management Tree ............................................................................................ 13 3.4. Importing Data Tree ..................................................................................................... 14 3.5. Legend Management Tree............................................................................................ 18 3.6. Field Sample Utilities Tree .......................................................................................... 23 3.7. Georeferencing Tree..................................................................................................... 28 3.8. Transforming Vector from unknown units to known units.......................................... 28 3.9. Coordinate Conversion Tree ........................................................................................ 38 3.10. Raster Utilities Tree ................................................................................................. 43 3.11. Drawing By Polygons Tree ...................................................................................... 54 3.12. Assigning the LCCS legend to the polygons ........................................................... 63 3.13. Drawing by Arcs and Points Tree ............................................................................ 67 3.14. Advanced Topology Tree......................................................................................... 72 3.15. Extra Layer Utilities Tree......................................................................................... 78 3.16. Multiple Windows Tree ........................................................................................... 81 3.17. Database Management Tree ..................................................................................... 84 3.18. Exporting Data Tree ................................................................................................. 88 3.19. Printing Tree............................................................................................................. 90 3.20. File menu.................................................................................................................. 91 3.21. Edit Menu................................................................................................................. 92 3.22. Tools Menu .............................................................................................................. 94 4. OPTIMAL CONFIGURATION………………………………………………………92 5. BIBLIOGRAPHY ........................................................................................................ 104

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1. WHAT IS GEOVIS? GeoVis is a vector-based editing system specifically designed for thematic interpretation. Hence, it facilitates and speeds up all mapping activities based on remote sensing data. It is a user-friendly system that embeds the main tools of vector drawing and editing, including topological functions, with advanced capabilities of raster management and a direct link with LCCS (Land Cover Classification System). The GeoVis software has been developed by Italian software house Terranova. The live-link with LCCS makes it possible to immediately assign a specific land cover class to a polygon. The resulting classified vector map is a final product and can be exported to e.g. ArcView to perform further GIS based manipulation or modelling. This document will describe in practical terms the necessary steps beginning from the start of importing the satellite date to exporting the product. These guidelines are made very descriptive and are visually documented. We will start with the LCCS software, as the user has first to compile his specific legend according to which the interpretation of the imagery will be done. This is covered very briefly as it is not the focus of this document. The second part covers the GeoVis software and will guide the user through the various steps to proceed from the initial data import to the final land cover product.

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2. LCCS

2.1. Making a legend It is a requisite that staff compiling a land cover legend are extremely familiar with the ecological situation in the country. Ecology – earth sciences experience is more required than computer skills (not for GeoVis though!!). The opening screen looks as follows:

When no legend exists, choose the “Classification” button . The first phase of the classification is a dichotomous phase (only yes-no divisions are possible) and guides the user into one of the eight primary land cover groups.

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The above diagram shows the screen of the dichotomous phase. Once the primary class is selected, the user can go into more detailed definition through a modular and hierarchical approach by clicking on the arrows below the 8 primary land cover groups. The user can now select the various ‘classifiers’ and their characteristics.

NB: to produce a predefined legend, the user should be familiar with the concepts of LCCS. Please refer to the LCCS manual for more details.

To quit building a class

Go back one level

Go to the ‘legend management’ menu

Image database query

Help on the classifier codes

Complete on-line help

View the status of the current class

Add the class to the current legend

Go to the ‘attribute’ menu

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2.2. Viewing the Legend The legend can be viewed through the Legend management menu. This menu can be reached

from the opening screen or from the menu bar in the ‘classification’ section

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Click on the ‘display ‘ button to view the legend or to print the legend in its structured format.

Click on the ‘Edit...’ button to add user labels and/or a description of the class.

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The original LCCS Code contains much information, but the codes are not easy to memorize. Therefore, only the user labels from the LCCS system are stored in the landcover shapefiles. The user label is the map code to be seen inside the polygon when using GeoVis. If the User label is not present in the LCCS legend then one cannot use the LCCS legend to assign polygon codes in GeoVis. The user labels are unique and if necessary it can be used to link back to the original LCCS Code. The user can supply his own code, but is recommended to use the codes developed by Africover. A complete list of these User Labels can be found as an appendix to the Africover Production Chain manual.

2.3. Save and export the legend A legend can be saved with a new name within the LCCS database by clicking the ‘save’ button. To view the legend in GeoVis you have to save the legend and give it a new name. When you open the LCCS legend in GeoVis, it will be available for you to work with. LCCS will automatically save the active legend while exiting. BEWARE: A number of legends can reside within the LCCS database. The last one used is the one that will be active when re-opening the database. It is recommended to always check which legend is active by going to the edit or display modes. If the required legend is not the active one, then go to the ‘retrieve’ button and select the appropriate legend. By pressing the ‘export’ button, a menu comes up, showing the various export possibilities. BEWARE: Before being able to export, an empty file will have to be made before, outside the LCCS program.

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Create empty files with the notepad (for .txt and .htm files); with excel for .xls files and within ACCESS for .mdb files.

The legend remains ACTIVE in LCCS!!! Beware NOT TO OVERWRITE the LCCS95 or LCCS 97 files, as these are the original LCCS database and user interface files.

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3. GEOVIS To launch the GeoVis software click the appropriate shortcut on the desktop:

GeoVis will open with a blank screen, ready to start a new project or open an existing one. The main functions and tools are grouped in a logical manner in the Action tree tools. The action tree tools represent a logical path in the data management process. You will not use all the available tools, only a few that are useful to and speed up your work will be dealt with. The tool you use most often will be put on your user defined toolbar and you will probably no longer work with the Action Tree tools.

wMenu Bar Main Toolbar

Help Functions Actions Tree Tools User defined tool

Theme windo

bar LCCS Legend

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We begin with the Help functions and then continue with the tools on the Main Toolbar and the action tree functions.

3.1. Help Functions These are very important in any software package because they aid the user in learning the software. GeoVis has a help window and three Help buttons. The Help window displays what a command in the action tree does. Highlight a command in the Action Tree and the command function is displayed in the Help window as below.

The first Help button labelled ‘Help’ opens the GeoVis Help document where you can find the functions of all the tools and menus available in GeoVis.

The Help button labelled ‘User’ allows the user of the software to create his own help notes. Highlight the tool; click the User Help button and the Edit the document to create your own notes.

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The last button, the FAO Help button , links you to the FAO website where you can find last minute information and tips about GeoVis.

3.2. Main Toolbar

Zoom Tools

Zoom Inclick)/ Z(right clPan

Zoom Window

Zoom to scale

Redraw

Zoom out

Zoom in Zoom to selected

Zoom all extents

Cut, Paste, Copy

Paste features Copy

features

Cut features

Zoom previous

(left oom out ick)

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These work in the same way as the normal windows commands. Measure Tools

Click the tool and click a line or polygon defining the area you would like to measure. The result is displayed in an Information box.

Selection Tools

Measure linear distance Measure

rectangle area

Measure polygon area

Default status (disables the current command)

Select Points

Select Arcs

Select Polygons

Select None

Invert selection

Identify feature

Find

The select tools work by clicking on the feature. Hold the shift key in to select more than one feature. The Identify tool displays information for the feature that you click on. The Find tool allows you to type in a value or string and then selects and zooms to the first feature that matches the criteria. All the functions of the various Action Trees are now reviewed.

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3.3. Project Management Tree

This is where you control your project. You can save and open projects and add and delete layers from your project. When you save a GeoVis project, it is saved in a file called *.tnp (Terranova Project).

Project file

Project Folder

In the above example, a project called landcover has been saved in the Projects directory. Note that when you save the project, GeoVis also creates a folder with the same name as the project. Inside this folder, you will find three folders:

• Extra Layer • Main Layer • Sample Fields

Inside each of these folders, GeoVis automatically creates three default shapefiles, one each for points, lines and polygons. These are needed by GeoVis for shapefile topology. Terranova has decided to use ESRI shapefiles for easy integration with ArcView GIS software.

New Project: Closes the current project and opens an empty new one. If current project has not been saved, the program asks confirm to save changes.

Open Project: Ask for an existing project (*.tnp) and closes the current project. If current project has not been saved, the program asks confirm to save changes.

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Save Project: Save changes of current project. If user has not yet defined the path name of the project, a dialog box will be opened to select the destination file.

Save Project As: Open a dialog box to select the file name to save current project.

3.4. Importing Data Tree This is where all raster and shapefile data is imported. When importing, GeoVis puts these raster and vector layers into the Main Layer.

Importing Raster:

Open an existing raster file (TIF, BMP, JPG, PNG, TNI, BIL, BIP, BSQ).

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You are able to import the whole image, quarter sub-scenes or even smaller sub-scenes, depending on the area being updated. If you know the pixel parameters for your area you can even customise the area being imported by typing in the pixel values. Always click the option to optimise raster loading to reduce either time or space.

Importing Raster By Bands: Open an existing raster file (TIF, BMP, PNG, JPG, TNI, BIL, BIP, BSQ) by the red band, the green band and the blue band. In this way, you are creating what is called a colour composite. A colour composite means that GeoVis will visually combine three layers of primary colours, a RED colour layer, a GREEN colour and a BLUE colour, in order to obtain a coloured image on the screen. It will be required to indicate which of the Landsat single bands will be assigned respectively to the RED, the GREEN and the BLUE colour planes. You will not be using the import by bands tool because the 432-colour composite has already been done in the image you will be using.

Importing Radex Theme: Open an existing RDE file from a connection with a TN-RaDEx server. RaDEx is a compression algorithm that optimises the display of raster datasets. When you import a raster dataset using the ‘reduced time’ or ‘reduced space’ options, GeoVis automatically creates an .rde file for allowing quick viewing of images when zooming in or out. It is based on pyramids, which record the original data in decreasing levels of resolution. The coarsest level of resolution is used to quickly draw the entire dataset. As you zoom in, layers with finer resolutions are drawn; performance is maintained because you're drawing successively smaller areas.

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Select the Radex file (*.rde) and click OK. A user and password are not required.

Once you have selected the *.rde file, choose the UTM zone you would like to work in.

Importing Additional Raster: Imports a raster to a multiple window. If there is no additional window and error

message will be given: . If you receive this error, please refer to section 3.16. If you already have a multiple window open, you will be asked which window you would like to import to and which file type you would like to import.

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Choose an option, click OK and proceed as for Importing Raster or Importing Radex commands.

Importing Polygons: Open an existing Shapefile with polygon features. This option along with the following two, allow the loading of existing shapefiles into GeoVis. Each option corresponds with the feature type of the original shapefile. These shapefiles will only overlay with raster datasets and vector layers of the same projection. Make sure then that all the data that you will work with in GeoVis is in the same projection.

Importing Arcs:

Open an existing Shapefile with arc features.

Importing Points: Open an existing Shapefile with point features.

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3.5. Legend Management Tree

Launch LCCS This launches an external session of the LCCS Application. The first time you use this tool; you will be asked where the LCCS install directory is. You can then navigate to the folder where you installed LCCS (the default is c:/program files/LCCS) and then click OK. You only have to do this once and GeoVis will remember the path to LCCS and automatically open it when you click the Launch LCCS button.

Open LCCS Style Legend Open a legend in LCCS style. This opens an existing legend that has already been created using LCCS. All LCCS legends are saved in a *.mde file and within this *.mde file you can choose the legend applicable to you.

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Once you have chosen the Legend to use and the appropriate fields you click OK and the LCCS legend will display as shown below.

You will notice eight numbered buttons at the top of the legend.

These correspond to the eight major classes of LCCS. You can display all the classes at once or only one at a time. The example above shows all of the eight classes ticked (and therefore visible in GeoVis) and class 7

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(Artificial waterbodies, snow and ice) is expanded to show all the classes that fall under that major class. If you click on one of the classes, you will see the LCCS code, the classifiers used for that class, the LCCS user label and the user description for that class. All this information was created when defining the legend in LCCS. You can label the polygons by clicking the tick box next to labels and you

can control the size of the labels by using the slide bar . You can assign symbology to the polygons by double clicking in the square between the tick box and the label or to quickly assign colours to all the classes you can use the Random Colour button .

In order to start an external session off LCCS, click the Launch LCCS button . If you make any changes to the legend, click Refresh Legend to update the changes made.

Another feature of GeoVis is related to the Minimum Mappable Area. This is the smallest area that can be shown on a map i.e. the smallest polygon that can be made in GeoVis. This is flexible in that you can specify the Minimum Mappable Area for each of the eight major land cover types from which the classes are derived. To do this right click on one of the major land cover groups. The menu below will appear and you can type in the minimum polygon size.

If you draw a polygon and try an assign an LCCS class to that polygon, you will get the following message if the polygon is smaller than the minimum mappable area.

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This is the pre-defined legend from LCCS that you will use to assign classes to your landcover polygons. This will be dealt with when we get to the Drawing By Polygons tree.

Edit LCCS Style Legend Modify a legend in LCCS style. You can modify and edit the LCCS legend directly in GeoVis. This is not advisable, as you need to be an expert in LCCS and GeoVis to be able to do this. You also need to have a thorough knowledge of the LCCS codes, classifiers and labels. Consequently, it will not be dealt with in this manual.

Show LCCS Legend Shows the current LCCS legend window.

Hide LCCS Window Hides the current LCCS legend window.

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Customize Polygons Symbology As mentioned under the previous heading, you can customise the Symbology for your polygon data. You can customize the representation of the polygons by setting the attribute of thematic visualization, the interval of classification and the symbol type.

Remember that you can also change the symbology of a polygon or class by clicking on the square next to the label in the LCCS legend.

Click to change symbology

Customize Arcs Symbology Customize the representation of the arcs by setting the attribute of thematic visualization, the interval of classification and the symbol type. A similar menu to the one shown under the Polygon Symbology will be available.

Customize Points Symbology Customize the representation of the points by setting the attribute of thematic visualization, the interval of classification and the symbol type. A similar menu to the one shown under the Polygon Symbology will be available.

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3.6. Field Sample Utilities Tree

Importing Samples Opens sample fields database. Use this option when a Field Sample database already exists. Double click the import icon and navigate to where the database resides on your hard drive. Notice that only Access (*.mdb) files can be imported. Choose the correct file and click Open.

GeoVis will then tell you how many field samples were imported from the database.

The field sample database will appear as in the diagram below. You can view the field samples as well as edit the data. Those who have completed the field survey forms

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while visiting the samples sites, will recognise that the sample fields editor below has the same information as the field survey forms. This allows quick and easy input of the field survey forms into the Field Samples database. Notice the tabs across the top of the form where different types of information can be input. The General Information and Codes tab (shown below) records the Sample number, date, time, observer details and the LCCS code for that location.

The next tab is the coordinate location tab (shown below) records the X and Y coordinates of the observer and records the position for the observer relative to the sample location. It also records the distance from the sample location.

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The third tab (shown below) is the Field Photo tab. This allows the user to link the field photographs to the field sample information. First click on the direction in which the photograph was taken and then select the appropriate photograph for that location. Notice that when a photograph is available, the direction tabs appear in blue.

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The last tab (shown below) allows for the input of any other relevant information that the observer may feel is important to the sample location. A brief description of the location as well as any information regarding access to the sample site should be included. Rather include too much information than too little as this description might aid in the interpretation of a difficult landcover polygon.

Edit Samples Modify a sample field’s database. Once the database has been imported, one can start editing the records in the database by clicking the tick box to enable editing

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Show Samples By clicking on this button, you can switch on sample fields layer. This will draw the point locations for the field sample using the coordinates that were input in the Field Sample database.

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Hide Samples This button will switch off the sample fields layer.

Identify Samples Show sample fields information. This allows you to view a sample point and display the information for that sample point. Once you have imported your samples, double-click the Show Samples tool to view the points. If nothing appears on your screen,

click the Zoom All button on the Tool bar. When all the points are displayed, zoom to the point you are interested in, double-click the Identify Samples tool and draw a block around the field sample of interest.

The information page for that sample will then be displayed for you to view or edit.

Close Samples Close sample fields layer. This option removes the sample field’s database from the GeoVis project.

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3.7. Georeferencing Tree

Add GCPs Insert the GCPs (Ground Control Point) specifying the coordinate of destination point.

Delete GCPs: Delete existing GCPs (Ground Control Point).

Delete All GCPs Delete all existing GCPs (Ground Control Point).

Transform Using GCPs Transform the coordinates of selected layers using the GCPs (Ground Control Point). This function is enabled if the GCPs are two or more.

The following procedure details how to georeference vector data using GCPs from an UN-referenced topographic sheet. The procedure also introduces the Export data tree and the Drawing by arcs and points data tree, which will be dealt with later in this manual. The procedure can be summarised as follows:

• Import the un-referenced image. • Digitise the vector data you would like to be transformed. • Export the vector data as a backup. • Add the GCPs and type the known coordinates. • Transform the vector using the GCPs. • Export the transformed vector.

3.8. Transforming Vector from unknown units to known units

• Open the scanned topographic map in GeoVis using the import raster option under the Importing Data tree. Import the whole image.

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• Find a point or points on the topographic sheet that you will be able to find on an image (for example a road intersection).

Add the points using the Add Points command found under the Drawing by Arcs and Points Tree. Double-click on the Add Points command and using the cross-hairs, add the point to the main layer. After adding the point, hit the escape key or right mouse button to disable the command.

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• Once you have finished adding the points, you can save these untransformed points to a shapefile using the Export Data tree, Save Points as option. This allows you to create an automatic backup of your points, in case something goes wrong during the transform process.

Make sure you save the file as an ArcView shapefile and give it a meaningful name.

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• Find the tic-marks at the four corners of the topo-sheet and write down the co-ordinates for each point. The co-ordinates are read off the topo-sheet.

Tic-mark for GCP 1 X = 475 000 Y = 9 530 000

• Add Ground Control Points (GCPs) at the crosshairs at the four corners of the

topo-sheet. Click on the Add GCPs button and the click on the desired GCP location. As soon as you place a GCP, an input box will appear where you can enter the destination coordinates. Start at the top left corner and add the GCPs

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in a clockwise direction. In the destination point box, type in the X and Y co-ordinates that you wrote down in the previous step.

Do this for all four GCPs.

• Double-click the Transform using GCPs command found under the Georeferencing tree. The following transformation dialog pops up.

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Important things to notice are the GCP number, the X and Y co-ordinate in screen units and the new transformation coordinates that you typed in. NB: Keep in mind that the coordinates you typed in are from the topo-sheets and therefore in the projection of the topo-sheet.

• Now click the Save report option to capture the information shown in a text file.

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• Click the Perform Transformation button to complete the transformation process. Select the themes to transform, making sure that only the points layer is selected.

• Click OK and your points will be transformed using the specified coordinates.

Zoom to full extent and then to the points to see them in GeoVis.

• Export these newly transformed points to a shapefile from GeoVis.

• Close GeoVis and open ArcView and load the Projector and Datum Conversion extensions. Add the transformed point shapefile.

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• You are now going to project the transformed points from the input topographic sheet projection to the projection matching the image. This is done so that the transformed points and the image will overlay in ArcView and in GeoVis.

• Specify the input projection and select Geographic as the output. Your file is now

in geographic co-ordinates, but remember that it is still in the datum used by the topo-sheet. You would like your points to be in WGS84 datum. Save your file to a new shapefile and add it to your view. Make this new theme active and click on datum conversion. Select the input datum (the one that was used by the topo-sheet). Select the output datum to be WGS84. The file is now saved with the new datum.

• Now project the points to the projections matching your image. Your input

projection will be Geographic and the output units will be metres. Specify the output projection parameters. Once the process is completed, load the points and the satellite image into ArcView and then GeoVis to make sure that the two overlay.

Add Links Insert oriented links. A situation might arise where your data seems to be offset equally in all directions from your image. This could be due to your projections not being the same or it might be slight errors in digitisation. In order to correct these errors, a transform using links can be used. The diagram below shows the polygon offset from the image. We are now going to correct this using transform using links.

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Double click the Add Links button and add the link as shown. You need a minimum of 3 links to be able to transform your data.

If a mistake is made you can use the Delete Links button to delete links one at a

time or you can delete all the links using Delete All Links. Once you have finished adding links, you can transform the data.

Transform Using Links Transform the coordinates of selected layers using the links. This function is enabled if the links are two or more. When you double click the button the transformation report will be displayed. You can also save the transformation report to a text file for future reference. This transformation reports is similar to the once in the Transform by GCP function. When you are satisfied, click the Perform Transformation button.

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You will then be asked which layer should be transformed. In the example below, it is the polygons on the extra layer that will be transformed.

Click Ok and your data will be transformed. Notice that the polygon in the example now has a much better fitter with the image.

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3.9. Coordinate Conversion Tree

Coordinate Conversion Convert geographic themes between different coordinate systems. In the example that we are going to look at, a polygon theme in geographic coordinates is going to be converted to UTM Zone 36 to overlay with the raster image. The first step is to load the raster and vector data into GeoVis. You will notice that the two themes do not overlay. Double click the coordinate conversion tool and choose the layer that needs to be converted.

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Click OK and you will be asked to enter the INPUT projection (the projection your data is currently in). In this example, it is geographic WGS 84. Once that is complete, enter the OUTPUT projection (what you would like your data to be projected to). In this case, it is UTM Zone 36. Tip: you will notice that there is a UTM Zone N (North) and a UTM Zone S (South). Choose North if your data is in the Northern hemisphere and South for the southern hemisphere. In countries across the equator, it has to be one or the other. N indicates that there is no Y-shift or false northing. S indicates a Y-shift of 10 000 000 (false northing). This shift is done for the southern hemisphere so that all coordinates have a positive value. In the example we need to choose UTM Zone 36 S because the image is in UTM 36 with Y-shift or false northing of 10 000 000.

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You have the option to save the description of your conversion and you can save the conversion process so that next time you can just choose the conversion file and all the parameters will be there. This is a nice feature since you don’t want to have to choose the INPUT and OUTPUT projection every time you have a lot of data to convert.

If you do save the conversion file, make sure you give it a descriptive name so you know what conversion type is.

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Once you are happy with your input and output parameters, click OK and file will be converted to the new coordinates. Your data now overlays with your image but remember your file has only been converted on the fly in GeoVis. To make the conversion permanent you need to export the file to a new name.

Translate Translate selected layers, defining the direction and the amount of translation with the cursor. Translation moves the selected layer in a direction specified by you. You can also specify the distance to translate by in the X and Y direction.

Double click the translate tool and click in the view to specify the beginning and end of you arrow. Select the desired layer and click OK. You layer will be moved in the desired distance and direction.

Rotate Rotate selected layers, defining the centre and the radius with the cursor. Double click the Rotate tool and draw the rotation circle and radius in the view. You can also type in an angle. Select the layer you would like to rotate and click OK. Your selected layer will be rotated around the angle you specified.

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Coordinate Calculator Conversion tool to transform pairs of points between different coordinate systems. Select the INPUT coordinate system and the desired OUTPUT coordinate system. Type in the Input X and Input Y coordinates and the coordinates are automatically calculated in the specified OUTPUT coordinates on the right hand side of the coordinate calculator.

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3.10. Raster Utilities Tree

Magic Wand and Magic Wand Options The Magic Wand adds polygons into the active polygon theme using an automatic classification algorithm that is set by the user in the Magic Wand Options. It is advisable to set the magic Wand options first before using the Magic Wand. Double-click on the Magic Wand Options button and the setting panel will be displayed.

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Here the user is able to set parameters for the automatic classification. The threshold, tolerance and seed pixel are all parameters that can be used to modify the automatic classification procedure. The meaning of each is beyond the scope of this manual but can be found in any remote sensing textbook. It is sufficient to say that they all define how the algorithm searches for pixel values related to the pixel that is clicked with the Magic Wand. Notice that the polygons acquired are fully topological and the user is even able to set the topological method of acquisition and the amount of vertex detail that is captured.

It is advisable to keep the topology active at all times and to set the vertices to medium. Too many vertices lead to a large dataset. Once you have set the topology acquisition and the vertex detail, return to the pixel

selection tab. Set the region of interest by clicking on the button. Draw a polygon around the area you would like to be mapped in the view. Right-click to end.

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The reason why the ROI needs to be set is so that the automatic classification doesn’t work on the whole image (this would require too much PC memory and processing power). Rather limit the area you would like to capture. Once you have set your ROI and tolerances you can capture your area. Note that you also have the option to use the original pixel values or the stretched values. Keep you Options window open and double-click on the magic wand tool. Move into your view and click once on a pixel in the area you would like to capture. The result looks as follows:

Notice that the Acquire, No Holes and Rest buttons now become active in your Options window. If you are happy with the selection you can press Enter on the keyboard or click on acquire. If you are not satisfied, you can set your tolerances to different levels and then click again in the view with the Magic Wand. When you are satisfied with the result you can capture the polygon by clicking on the no Holes option. This captures the polygon but removes any holes (pixels that were not inside the search tolerances) that are inside the main polygon. Once happy with the result you can code the polygon with the appropriate LCCS class. See section 3.12 for the procedure.

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Polygons/Raster Compare Compares a polygon layer and a raster image, and adds a set of summary statistics concerning the correlation between vector interpretation and raster data to the attribute table. Load the raster image and the polygons you would like to compare. Double click the Polygons/Raster Compare tool.

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The process of comparing will take some time depending on how many polygons are in your dataset. A progress window will appear so you can track the process.

The result is a table of summary statistics, similar to the one below.

The process calculates the mean pixel values within the polygons of a particular class, in the red, green and blue band. The fields are defined as follows: P_Mean_R - Mean value of Red component for all pixels of image that fall inside the polygon. P_Mean_G - Mean value of Green component for all pixels of image that fall inside the polygon. P_Mean_B - Mean value of Blue component for all pixels of image that fall inside the polygon. C_Mean_R - Mean value of Red component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon. C_Mean_G - Mean value of Green component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon. C_Mean_B - Mean value of Blue component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon. C_StdDev_R - Standard deviation of Red component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon.

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C_StdDev_G - Standard deviation of Green component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon. C_StdDev_B - Standard deviation of Blue component for all pixels of image that fall inside every polygon having the same LCCS class as the current polygon. P_Accu - Accuracy of current polygon (how much polygon is similar to polygons of the same LCCS class: 0.0 means perfect accuracy). C_Accu - Accuracy of LCCS class to which current polygon belongs (mean accuracy for all polygons of the class).

Stretching Options Set the options of visualization of raster theme, by specifying the parameters for the three bands. Before moving on to the real interpretation and tracing polygons, some basic aspects of ‘preparing’ the image to increase and facilitate the interpretation of features of interest are explained. The Stretching Options button allows a professional job to be done on visually enhancing the image by manipulating the distribution of the pixels values relative to the dynamic range of colour distribution. Hereafter the basic principles of ‘stretching’ are explained without going into detail. For more information on this vast subject, professional literature will have to be searched. While GeoVis allows easy manipulation of colour ranges so that the un-experienced user can experiment without problem, experience in satellite image processing is required to obtain professional results. The satellite will see the earth through the atmosphere and from a high distance, some 850 km above the earth surface. Due to this, the image looks quite dull, as can be seen below.

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BEFORE STRETCH In fact, when looking at the pixel value range or histogram (obtained when double clicking the Stretching Options button), it can be seen that all values that make up the image are squeezed together. In this sense, these values use only a very limited part of the colour range available. This squeezed histogram can be ‘stretched’ to use the complete dynamic range. NB: Each pixel in each of the three bands gets one byte (8 bits) assigned to show its grey tone. This means that in one band a pixel can have a value ranging from 0 to 256 (the binary combination of 8 bits in that byte). So, the plane can be expressed as going from value 0 to value 256. The histogram below shows the corresponding shade of red for any pixel value. It can be seen that the red values are all clustered in a small part of the spectrum - only a part of the range is consumed)

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To make the image ‘more clear’ in the red band that range should be increased. This is done by dragging the maximum and minimum lines closer to the range of values. Having done this it can now be understood that the same pixel values are assigned a more complete range of the shades of red. This ‘stretching’ needs to be done for all three bands. Choose alternatively another band and look at the result on the screen.

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AFTER STRETCH

The above explained very briefly the principle of linear stretching. GeoVis provides the Auto Stretch options, which is a fairly good compromise to enhance the image so the less-experienced user can immediately see a ‘better’ image. If there is more than one raster in multiple windows, a pop-up window asking which raster to stretch will appear. Choose the window that contains the raster you would like to stretch.

The next three tools are all image conversion tools. They are mentioned here but are not dealt with in detail as they are beyond the scope of this manual.

8 To 24 Bits Conversion Raster conversion from 8 to 24 bits. This function modifies colour palette and file format.

24 To 8 Bits Conversion Raster conversion from 24 to 8 bits. This function modifies colour palette and file format.

8 To 1 Bit Conversion

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Raster conversion from 8 to 1 bits. This function displays an interactive graphic window and allows setting up the parameters of the transformation. Click the Build Histogram button and set your parameters for conversion, using the previews on the right as a guide. Once everything is set, click Run.

Clipping Clip raster data using a rectangle shape selected from the user. Click on the clip raster button and draw a rectangle where you want to clip. Click in one corner and move the rectangle to the size you require and click to end. This option is used when working with large images and you only need to work on a small user defined section.

Edge detection and thinning are image enhancement techniques but are not applicable to this manual.

Edge Detection Create a new raster from the active one, and enhance contours features (change of colours). The new raster become the active raster.

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Thinning Perform the erosion of linear features in a raster theme. The erosion function is cyclic and can go on until the thickness is more than one pixel.

Raster To Lines Automatic vectorization, starting from a raster theme and arriving to a vector based line theme. This function works on 1 bit data only (black and white images). Convert your image to 8 bit and then to 1 bit by using the above conversion tools. This tool is useful to capture lines on a topographic map. The data will have to be edited and attributes added after this process. Double-click the Raster to Lines tool, choose the line capture process and then click OK.

Raster To Polygons Perform an automatic vectorization, over a raster theme, builds the topology and create a polygon theme. This function only works on 1 bit images (black and white) and is useful for capturing polygons from topographic maps data. Double-click the Raster to Polygons tool, set the parameters for the polygon capture and click OK.

Close Raster Close the raster of the active theme.

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3.11. Drawing By Polygons Tree

It is highly recommended to use these tools for polygon editing, as it will avoid creating topology errors and therefore be less work for the user in the long run as they will not have to check for the errors afterwards.

Add Polygons Add polygons into active polygon theme. Click on the Add Polygons button and click the starting point for your polygon. Move your cursor around the polygon, clicking every time you would like to add a vertex. When you are finished digitising, right click to complete the polygon. The polygons get added to the active layer (the main layer by default). To disable the Add Polygon tool right click again or use the Esc key.

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You have a few options when creating new adjacent polygons by using the Shift and Ctrl keys. For example, you would like to add a polygon as shown below. The polygon on the left was added first and the one on the right is to be added to the layer.

1 2

1 2

NORMAL

The option above illustrates what happens when no button is pressed. Just left clicking and then right clicking to end the polygon. The polygon added first takes preference and the new polygon is added under the first one. The result is two polygons.

3

1 2

SHIFT KEY

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The option above illustrates what happens when the Shift button is pressed. Before starting to add the polygon, press the Shift key and hold it in while left clicking to add the polygon. Right click as normal to end the polygon while still holding the Shift key in. The result is three polygons with the third one being the area of overlap between the two polygons.

1 2

CTRL KEY

The option above illustrates what happens when the Ctrl button is pressed. Before starting to add the polygon, press the Ctrl key and hold it in while left clicking to add the polygon. Right click as normal to end the polygon while still holding the Ctrl key in. The result is two polygons but this time the one added second takes preference and is added over the first polygon.

Add Vertex To Polygon Add a new vertex to selected polygon and edit the existing ones. If your polygon is not quite right and you need to slightly adjust the borders, you can move vertices to new positions. Click on the Add Vertex button, click inside the polygon to highlight the existing vertices and then move a vertex by clicking on it and dragging to the new position.

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Remove Vertex From Polygon Remove vertex from selected polygon. To remove a vertex, click on the Remove Vertex button and then click on the vertex you would like to remove.

Split Polygon Split the selected polygon. Click on the Split Polygon tool; select the polygon you would like to split by clicking on it. It will then be highlighted in green. Now click the starting point of the line where the split should be, making sure to start outside the polygon. Click along the line to split until you get to the end where you will right click to end the line, again making sure to finish outside the polygon. The polygon will be split along this line and the overshoots you made at the beginning and end of the line will be deleted to preserve topology. NB: You cannot Undo while editing in GeoVis, so make sure you make no mistakes. If you do you will have to begin again.

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Start point

End by right clicking

Merge Polygons Merge two adjacent polygons. Click the Merge Polygon tool and then select the first polygon to merge. It will be highlighted in green as shown below.

Select first polygon to merge

Select the other polygon you would like to merge and the two separate polygons will be merged to form one. Right click or Esc to disable the merge operation. Be sure you know which polygons to merge before you begin as the Merge operation cannot be Undone.

Merge result

Select second polygon to merge

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Delete Polygons Delete the selected polygons. Click on the Delete Polygons tool and then click on the polygon to be deleted. The operation cannot be Undone.

Delete All Polygons Delete all polygons on the active layer.

Eliminate Small Polygons Delete polygons with area less than a specified value. The small polygons become part of the nearest one. Click on the Eliminate Small Polygons button. Type in the value – GeoVis will eliminate all polygons with an area smaller than the one you specify. GeoVis uses the map units of your data. Make sure then that your data is in metres.

After the task is complete, GeoVis will tell you how many polygons were deleted and there fore below the specified area tolerance.

Show Polygons Table Display the attribute table of active polygon theme. The attribute table is very similar to the attribute table functions of ArcView.

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The table toolbar looks like the one in the diagram below. A brief explanation of each tool (from left to right) follows.

Print - makes a print out of the table to the selected printer.

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Query - define a query by clicking on the attributes and operators. The Query button in GeoVis is very similar to the Query builder of ArcView.

You can create a New Selection, Add to a selection or Unselect using a query.

Find - find a record based on an attribute. You can specify which field you would like to search by checking the tick boxes next to the relevant field and you can also specify if you would like your search to be case sensitive by checking or un-checking the Capital/small letters tick box.

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Select All - Selects all the records in the table. Unselect All - Unselects all the records in the table.

Switch the Selection - switches the current selection in the table. If nothing is selected in the table and this button is clicked, it will select all the records in the table.

Promote Selection - promotes the current selection to the top of the table for easy viewing.

Original Order - if the table is sorted according to an attribute, this button will put the table order back to its original un-sorted state.

Sort Ascending - sorts the table in an ascending order based on an attribute. First make the field active by clicking on it and then sort by clicking on the Sort Ascending button.

Sort Descending - sorts the table in a descending order based on an attribute. First make the field active by clicking on it and then sort by clicking on the Sort Descending button.

Field Properties - shows the field properties of the active field.

Field Calculator - allows you to calculate the values of a field based on a formula that you define. All the tools described above are available in the menu drop-down lists as well.

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Reset Values to Zero - this tool sets the selected records back to zero. Be careful with this tool, as you cannot undo the operation. Make sure that you have the correct records when using this tool.

3.12. Assigning the LCCS legend to the polygons • Import an existing polygon shapefile and the raster image. If no polygon layer exists then

start creating one with the Draw Polygon tool as described in the Drawing by Polygons Tree.

• Open the applicable LCCS legend as described in the Legend management Tree. • You now have a polygon layer, the underlying satellite image and the LCCS legend open

in GeoVis. You can now begin to interpret the polygons and assign a LCCS code to your polygons.

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To assign the LCCS to legend to the polygons, follow the procedure below. • Locate the code you would like to assign in the LCCS legend. Highlight it and make sure

it is the one you want to use, by reading the LCCS label and User Description at the bottom.

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• Locate the polygon or polygons that you would like to assign this code to by zooming and panning in GeoVis. When you have found the appropriate polygons, double-click on the code in the LCCS legend.

• Move into the view and click on the polygon that should be assigned this code.

• The polygon will immediately change to the colour of the code in the LCCS legend and (if you have the label box ticked) it will display the label of the code that you just assigned as well.

• When you have finished assigning that particular code to all the applicable polygons, you

can right-click or hit the Esc key. This disables the code and you can move on to the next code in the LCCS legend.

• To verify that the code has in fact been associated to the polygon, select the polygon and

open the attribute table. Promote the selection and have a look at the attributes of the record.

Notice that the LCCSPerc is 100 %. This indicates that the polygon is homogenous and only made up of one landcover class (LCCS code). What happens in the case of mixed units and how do you assign them? • Assigning mixed units is not as difficult as it sounds. First, highlight the class that forms

the majority landcover in the mixed unit.

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• Now, while holding in the CTRL key, select the LCCS code (landcover class) that makes up the rest of the class.

Two codes

• You will notice that the LCCS label and User Description stays the same as the first class

you selected. So how do you know that you have selected two classes? Look at the Code field. There are now two codes separated by a backslash ( / ). This LCCS code indicates the first and second class of landcover.

• When you have selected all the classes that make up the polygon (you can select more

than two), double-click the last class you have added (still holding the CTRL button in). • Now click in the polygon that should be assigned these classes in the same way as before.

• Your polygon will be shaded and the label will be the code of the classes you assigned. • Select the polygon and go to the attribute table.

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• Notice that both the LCCSCode and UserLabel fields have two classes assigned, indicating the two classes you selected in the LCCS legend. Notice also that the LCCSPerc field is now 60 / 40 %. This is the split for a mixed polygon of two classes; with the first class you selected being assigned 60 %.

• Below is the result of choosing three classes.

3.13. Drawing by Arcs and Points Tree

Add Arcs Add arcs into active arc theme. This is ideal for digitising roads and rivers on-screen directly from the image. Click on the Add Arcs button and digitise the arc in the

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desired position in the view by left clicking to create a vertex. Right click to end the arc.

Add Vertex To Arc Add a new vertex to selected arc. Select an arc and click on the Add Vertex button. With the cross-hair that appears, click on the place where you would like to insert a vertex. You can move the vertices by clicking on them and dragging them to the new position. Right click or Esc to disable the command.

Remove Vertex From Arc Remove vertex from selected arc. Click on the Remove Vertex button and click on the vertex to remove with the cross-hair. Right click or Esc to disable the command.

Split Arc Split the selected arc. Click on the Split Arc Tool and select an arc to split by clicking on it. Now click on the position where the arc should be split. The result is two arcs split at the position as indicated. This operation cannot be undone.

Delete Arcs Delete the selected arcs. Click the Delete Arc button and select the arcs to be deleted by clicking on them with the cross hair. The operation cannot be undone. If you delete an arc by mistake, it will have to be added again.

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Delete All Arcs Delete all arcs of the active layer.

Show Arcs Table Displays the attribute table of active line theme. The table functions are the same as for the polygon attribute table.

Add Points Add points into active point theme. Ideal for adding the location of point features such as Ground Control Points. Click ion the Add Points button and click in the view to indicate the location of the points. A new point feature will be added to the active layer.

Delete Points Delete the selected points. Click on the Delete Points tool and select the points to be deleted by clicking on them with the cross-hair.

Delete All Points Delete all points from the active layer.

Show Points Table Displays the attribute table of active point theme. The table functions are the same as for the polygon attribute table.

Clean Arcs Removes topological errors from the line theme, creating nodes at every intersection and deleting dangle nodes. Click on the Clean Arcs button and the following form will appear:

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You have the option to choose to keep the existing codes or to create new ones after the clean operation. You can also specify the fuzzy tolerance. All vertices within this fuzzy tolerance radius will be snapped together to make one arc. Below is an example of the arc attribute table before the clean and after the clean with the Keep Arcs codes option checked. Notice that arcs that have the same code will be joined to form one arc if they are next to each other.

BEFORE CLEAN

AFTER CLEAN

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Clean Polygons Clean the lines and create polygon topology. You can create polygons from the existing line theme using this option. You will probably not use it much as you will create the landcover classes as polygons from the beginning anyway.

Specify the fuzzy tolerance and the dangle length. The fuzzy tolerance is the same as was explained previously. The dangle length specifies a tolerance to delete small dangling arcs. Any arc smaller than the dangle length will be deleted.

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Above is the cleaned polygon from the original arc theme. GeoVis will also let you know how many polygons were built from the arc theme.

Show Topology Errors Display topological errors as dangle nodes, intersections, and multiple labels. This is not yet operational in this version of GeoVis. It will enable you to view the topology errors on-screen.

3.14. Advanced Topology Tree

Clean Arcs Remove topological errors from the line theme, creating nodes at every intersection and deleting dangle nodes. Same function as the one explained under the Drawing by Arc and Points Tree.

Clean Polygons Clean the lines and create polygon topology.

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Same function as the one explained under the Drawing by Arc and Points Tree.

Show Topology Errors Display topological errors as dangle nodes, intersections, and multiple labels. This is not yet operational in this version of GeoVis. It will enable you to view the topology errors on-screen. Same function as the one explained under the Drawing by Arc and Points Tree.

Flip Arcs Flip the direction of select arcs. Changes the direction of the arcs. Not important for this manual.

Centre Centroids Moves the label to the centroid of the polygon.

Eliminate Small Polygons Deletes polygons with an area less than a specified value. The small polygon becomes part of the nearest one. This is the same function as discussed under the Drawing by Polygons Tree.

Generalize Arcs Delete useless vertices and simplify the arcs. This helps to reduce the file size of large datasets. It is useful when the lines have been digitised at a large scale but the data will only be used at a small scale. It eliminates all vertices within the specified tolerance.

BEFORE GENERALIZE

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AFTER GENERALIZE

Unsplit Arcs Delete pseudo nodes in arc features, specifying the dissolving criteria. This dissolves the arcs based on the criteria you specify. All lines of the same type will be joined to form one line if they are adjacent to each other.

Dissolve Polygons Dissolve adjacent polygons, specifying joining criteria. If polygons with the same code are adjacent to each other, they will be dissolved to form one polygon. This helps reduce the size of the dataset and is useful when aggregating data. Click the Dissolve tool and mark the dissolve criteria in the dialog box that appears. GeoVis will the process and will notify you on the progress of the operation.

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BEFORE DISSOLVE

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AFTER DISSOLVE

The GeoVis dissolve operations are not entirely free of bugs yet. For the time being, you are urged to use the dissolve function of ArcInfo to ensure the correct result. Remember that the operation cannot be undone and GeoVis works directly on the dataset. You are not asked to save an output. Always make a back up before running these operations. If your result is not the one you desired, you can always go back to your original dataset.

Polygons To Arcs And Points This tool creates boundary arcs and points inside polygons.

You have the option to create both arcs and points from the existing polygon theme.

Remove Dangles Snap dangle nodes within a distance and delete dangle lines smaller than a specified length. It should not be necessary to use this option since when adding polygons in GeoVis, topology is already enforced and there should be no dangling nodes. This is useful for cleaning up data from another source.

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The first tolerance setting is the distance a line can move to snap to a node. The second tolerance deletes all dangling arcs below the specified tolerance. This process is automatic.

Remove Dangles Interactively Open a window to interactively remove dangles in the active theme. You have the option of deleting dangles interactively. This should be used when there are only a few dangling nodes in the dataset. Clicking on the button opens an interactive window where you can view all the dangling nodes. You can set the snapping type and the tolerance levels as well. These tools are beyond the scope of this manual, as all topology issues will be handled in ArcInfo.

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3.15. Extra Layer Utilities Tree

Importing Extra Polygons Open an existing Shapefile with polygon features. Imports a polygon shapefile to the extra layer. The process is the same as explained under the Importing Data Tree, except the theme is put on the extra layer instead of the main layer. The extra layer is useful when you have ancillary data that will help you to interpret landcover.

Importing Extra Arcs Open an existing Shapefile with arc features. Imports a line shapefile to the extra layer. The process is the same as explained under the Importing Data Tree, except the theme is put on the extra layer instead of the main layer. The extra layer is useful when you have ancillary data that will help you to interpret landcover.

Importing Extra Points Open an existing Shapefile with point features. Imports a point shapefile to the extra layer. The process is the same as explained under the Importing Data Tree, except the theme is put on the extra layer instead of the main layer. The extra layer is useful when you have ancillary data that will help you to interpret landcover.

Customize Extra Polygons Symbology Customize the representation of the polygons by setting the attribute of thematic visualization, the interval of classification and the symbol type. The procedure is the same for setting Symbology for the main layer as discussed under the Legend Management Tree.

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Customize Extra Arcs Symbology Customize the representation of the arcs by setting the attribute of thematic visualization, the interval of classification and the symbol type. The procedure is the same for setting Symbology for the main layer as discussed under the Legend Management Tree.

Customize Extra Points Symbology Customize the representation of the points by setting the attribute of thematic visualization, the interval of classification and the symbol type. The procedure is the same for setting Symbology for the main layer as discussed under the Legend Management Tree.

Show Extra Layer Switch on extra layer. This can also be done by using the Toggle Theme Window (F8).

Hide Extra Layer Switch off extra layer. As above.

Select Extra Polygons Select polygon feature in extra layer. Click this button before selecting polygons on the extra layer.

Select Extra Arcs Select arc feature in extra layer. Click this button before selecting arcs on the extra layer.

Select Extra Points Select point feature in extra layer. Click this button before selecting points on the extra layer.

Copy To Main Layer Copy extra layer into main layer. You can copy selected features from the extra layer to the main layer. When clicking this button you will be prompted to indicate the topological overlay method.

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Using the Over option means that the polygons from the extra layer take preference when pasting. The Under option indicates polygons on the main layer take preference. Using the Intersect option will create new polygons where the features from the main layer and extra layer intersect. Avoid using the Non-topological option because then polygons will be pasted on to each other and overlaps will occur.

Activate Extra Layer Makes the extra layer the current active layer. Can also be done using the Toggle Theme Window (F8). The green ball indicates which is the active layer. In the diagram below, the Extra layer is active.

Close Extra Layer Close extra layer level. This option removes the extra layer from the GeoVis project.

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3.16. Multiple Windows Tree

Windows Options There are 4 options for the multiple windows: Unique window, two windows

(horizontally or vertically arranged) and four windows. Be aware that the more multiple windows you have, the more resources your PC will use. If you have data on 4 windows you will need a PC that exceeds the minimum requirements for GeoVis.

Load raster data to window 1 by importing data under the Importing data tree. Any vector data that is loaded (main layer or extra layer) will be visible in all the open windows. To import raster data to one of the other windows, use the Import additional raster tool. See section 3.4.

Syncronise Multiple Windows Once you have loaded all your data, you need to syncronise the windows so that you can view all the data at the same time. If you pan or zoom in one window, all the other windows that are syncronised will automatically update so that you are always viewing the same area, no matter what window you are in. Double-click the Syncronise Multiple Window tool and the following window will appear.

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The user is able to syncronise any of the multiple windows with the main window. You can specify to syncronise only the centre of the windows or only the zoom factor. It is recommended however to syncronise all the windows using the Syncronise All option. By doing this, only one click (indicated above) is required to syncronise all the windows. Be aware that the more windows are open, the slower the process of zooming and panning. Only put necessary data into windows and remove all un-needed data. The raster files should be in the same projection for the syncronise tool to work properly.

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The real power of the multiple windows can be illustrated by the following example. In the figure below, the Landsat image (in the main window) is obscured by cloud. The user can use auxiliary data such as a topographic map to aid the land cover mapping process. The user is able to draw a polygon on any window (in this case the topographic map in the lower window) and still update the Main Layer, where the land Cover polygons reside. In this way, the task of land cover mapping is made easier by allowing auxiliary information to be added and geo-syncronised with other data. Notice that the polygon drawn on the topographic map is displayed automatically in the main window with the Landsat image.

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3.17. Database Management Tree

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Define Polygons Table Define the structure of polygon table. This allows you to add fields to the table, modify existing fields and delete fields. You have the option of adding a list of standard fields to the table as shown below. The standard fields cannot be modified.

Add a new field by clicking New and typing in the name of the field. You need to also specify the type and width of your field according to what type of data you will be entering.

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When done, press OK and the field is added. If you make a mistake and you need to change for example the width of the filed, you can do so by clicking the Modify button. A nice feature of GeoVis is the Add Look-Up attribute button. This allows you to select attributes from an existing table. In the example below, we have linked to an external table that has values for aggregated agriculture. It contains a description and an id field. Select the look-up field. This is the field where you will be able to choose values available in the external table. You can also set computed fields, where a field in the polygon table will be calculated according to what you choose in another field. In this example, the field AGG_ID will be calculated according to what is chosen in the AGNAME field. This is a nice option because the description and its associated ID field will be automatically calculated just by specifying the value of one field.

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Once you have specified all the conditions, press OK. To view the options available to you in when assigning attributes, double click the applicable field in the Polygon attribute table and the available options will appear in a drop-down list.

Show Polygons Table Displays the attribute table of the active polygon theme.

Query Polygons Table Select polygons with a query on the related attributes. This is the same as the function explained under the Draw by Polygons Tree.

Define Arcs Table Define the structure of arc table. This is done in exactly the same way as explained above under Define Polygons Table.

Show Arcs Table Displays the attribute table of the active line theme.

Query Arcs Table Select arcs with a query on the related attributes. This is the same as the function explained under the Draw by Polygons Tree.

Define Points Table Define the structure of point table. This is done in exactly the same way as explained above under Define Polygons Table.

Show Points Table

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Displays the attribute table of the active point theme.

Query Points Table Select points with a query on the related attributes. This is the same as the function explained under the Draw by Polygons Tree.

3.18. Exporting Data Tree

Save Raster As Save the raster with a new name. You can choose between a number of image types and you have the option to save with or without LZW compression.

Save Polygons As Save the polygon theme with a new name. You can choose to save from the main layer or the Extra layer.

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The output can be as an ArcView shapefile or on ArcInfo generate format. Always use the shapefile option.

Give your shapefile a descriptive name and click Save.

Save Arcs As Save the arc theme with a new name. The same procedure applies as under Save Polygons as.

Save Points As Save the point theme with a new name. The same procedure applies as under Save Polygons as.

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3.19. Printing Tree

Page Set-up Set the printing options for your maps. Features that you can include are Title, North Arrow, Legend and Logo. The Page set-up form is shown below.

Printer Set-up Set the printer options. These are the normal print options for a Windows Printer.

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Print Print with the page set-up previously defined. This immediately sends your map to the printer selected above. Unfortunately, in GeoVis there is now option where you can Preview your map before printing.

3.20. File menu

New Project Closes the current project and opens an empty new one. If the current project has not been saved, the program asks confirm to save changes. Open Project Ask for an existing project and closes the current project. If the current project has not been saved, the program asks confirm to save changes. Save Project Save the changes of the current project. If the user has not yet defined the path name of the project, a dialog box will be opened to select the destination file.

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Save Project As Opens a dialog box to specify a file name to save current project. These are the same as discussed under the Printing Tree. Print Print with the page set-up previously defined. These are the same as discussed under the Printing Tree. Printer Set-Up Set the printer options. Page Set-Up Set the printing options. These are the same as discussed under the Printing Tree. Exit Closes GeoVis.

3.21. Edit Menu

Select None Deselect the current selection on the active layer. Invert Selection Switch the selection current selection on the active layer. Selecting Polygons

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Select Polygons (SHIFT+F6) Select polygon featured in map window. Select by clicking on the polygons to be selected. Hold the Shift key to select multiple polygons. Select All Polygons Select all polygon features in map window. Invert Selection Switch the current selection selection. Unselect All Unselect all polygon features in map window.

Selecting Arcs

Select ASelect a Select ASelect aInvert SSwitch UnselecUnselec

Selecting Poin

Select PSelect p Select ASelect a Invert SSwitch UnselecUnselec

rcs (SHIFT+F7) rc feature in map window.

ll Arcs ll arc features in map window. election

the current selection.

t All t all arc features in map window.

ts

oints (SHIFT+F8) oint features in map window.

ll Points ll point features in map window.

election the current selection.

t All t all point features in map window.

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3.22. Tools Menu

Project Settings

General Information Display general information about the current project and geographic themes.

You can also get information about each layer by selecting one of the Layer tabs.

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Project Options Allows the user to enter a brief description of the project as well as any notes.

Default Colour Select default colour options. This allows you to change the default Symbology for all layers and feature types.

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Drawing And Editing Options Setting options for drawing, digitising and editing functions.

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Magic Wand Options Sets the parameters for the Magic Wand. See section 3.10. Background Colour Select the background colour of the map window by selecting a colour from the colour palette that pops up. Coordinate visualisation Opens the Coordinate Conversion dialog. See section 3.9.

Show/Hide Components

Toggle Raster (Ctrl+F1) Show/hide raster theme. Toggle Arcs (Ctrl+F2) Show/hide arc theme. Toggle Points (Ctrl+F3) Show/hide point theme. Toggle Polygons (Ctrl+F4) Show/hide polygon theme.

Show/Hide Layers

Toggle Main Layer (Ctrl+F5) Show/hide main layer. Toggle Extra Layer (Ctrl+F6) Show/hide extra layer. Toggle Sample Fields (Ctrl+F7) Show/hide sample fields layer.

Show/Hide LCCS Legend Toggles the LCCS legend on and off.

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Toggle Active Layer

Toggle Active Layer (Ctrl+F8) Activate/Deactivate main layer/extra layer. Activate Main Layer Open a dialog box to select the active layer. Activate Extra Layer Make extra layer the active layer.

Interface Settings

Toggle Show/h Toggle Show/h Toggle Show/h

Toggle Show/hswitch o Toggle Show/hSwitch

Fill (F6) ide the fill.

Transparent (F7) ide transparent tool.

Theme Window (F8) ide theme window.

Actions Tree (F11) ide action tree. If you need to have a bigger view of your data, you can ff the Actions Tree by using this option.

User Defined Toolbar (F12) ide user defined toolbar. This is the Toolbar at the bottom of GeoVis. it on and off by using this option.

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Main Toolbar

Customize Customize main toolbar. Add or remove buttons from the main toolbar. You can also save the configuration of the main toolbar and load the default if necessary.

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Load Configuration Load main toolbar configuration. Reset Reset main toolbar configuration.

User Defined Toolbar

Customize Customize user-defined toolbar by adding and removing buttons as shown above. Put only the tools that you use most often on the User defined toolbar. You can also save your own configuration Load Configuration Load user-defined configuration toolbar. Reset Reset user-defined configuration toolbar. Save FAO Configuration Save FAO configuration toolbar. Load FAO Configuration Load FAO configuration toolbar.

Drawing Tools

Add Polygons (Ctrl+P) Add polygons into active polygon theme. This is the same as the tool as explained under the Drawing by Polygons Tree. Magic Wand (Ctrl+M) Activates the Magic Wand. This is the same tool as described under the raster Utilities Tree.

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Add Arcs (Ctrl+A) Add arcs into active arc theme. This is the same as the tool as explained under the Drawing by Arcs and Points Tree. Add Points (Ctrl+N) Add points into active point theme. This is the same as the tool as explained under the Drawing by Arcs and Points Tree. Add GCPs (Ctrl+G) Insert the GCPs (Ground Control Point) specifying the coordinate of destination point. This is the same as the tool as explained under the Georeferencing Tree. Add Links (Ctrl+L) Insert an oriented links. This is the same as the tool as explained under the Georeferencing Tree.

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4. OPTIMAL CONFIGURATION This section briefly describes the optimal hardware configuration for GeoVis and a screen capture of the optimal screen configuration for GeoVis is also given. This configuration is recommended for the user who already has a basic knowledge of GeoVis to be able to work as efficiently as possible. Linked to this are the shortcuts that have been given in brackets next to Menu tools throughout the manuals. These shortcuts eliminate the need for needless clicking of the mouse and searching for tools, as they are available immediately the use presses the shortcut key. Hardware recommendations

• Windows NT or Windows 2000. Problems have been experienced with Windows 95 and 98.

• RAM – the amount of memory is linked with the size of the image being processed. The recommendation is a minimum of 256 MB RAM.

• 800 MHz processor. GeoVis Configuration

2 3 4 5 6

1

7 8 9 10 11

This configuration is designed for efficiency when editing polygons and assigning LCCS classes to polygons. The main toolbar at the top and the User Defined Toolbar at the bottom have been customised by including only buttons that are regularly used.

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1. The view has been expanded to include as much of the image as possible. This is done by switching the Action Tree Tools (F11).

2. All the zoom tools are included on the main toolbar. 3. Copy, cut and Paste operations 4. Measure tools 5. Selection tools for points, lines and polygons. 6. Query tools 7. Project management tools on the User defined toolbar. 8. Raster and polygon import tools. 9. Open the LCCS legend and raster stretching options. 10. All the polygon editing tools. 11. Export polygons and layer management tools.

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5. BIBLIOGRAPHY Di Gregorio, A. & LJM Jansen. 2000: Land Cover Classification System – LCCS. Food and

Agriculture Organisation of the United Nations. Rome, Italy. Terra Nova, 2002: GeoVIS 1.0 Help. Terra Nova Geographic Information Systems, Rome,

Italy.

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