Tutorials for Web GISChangeMatters

ChangeMatters

Tutorial Overview

In this tutorial, you will explore Esri’s ChangeMatters viewer which uses Landsat Imagery to map land cover change. Furthermore, you will use the ChangeMatters viewer to examine various areas and consider the impacts of change on the surrounding landscape http://www.esri.com/landsat-imagery/index.html.

SkillsBy completing this tutorial, you will become comfortable with the following GIS skills:

Exploring Landsat imagery to visualize land cover change over time Using and interacting with a Web GIS Interpreting a land cover change map

Time RequiredThe following is classroom time required to complete this tutorial:

15-20 minutes

Materials RequiredTechnology:

Internet browser (e.g. Internet Explorer, Firefox, Chrome) Adobe Flash plug-in

Production DateThe Education and Research Group at Esri Canada makes every effort to present accurate and reliable information. The Web sites and URLs used in this tutorial are from sources that were current at the time of production but are subject to change without notice to Esri Canada.

Production Date: January, 2013

Background Information

ChangeMatters is an interactive, simple-to-use application for visualizing and analyzing Landsat data in a region of interest. It accesses Landsat image services on ArcGIS Online to provide multiple imagery products from one set of source data. With ChangeMatters, you can see how any area in the world has changed over time by viewing different years, side by side, to make comparisons. The ChangeMatters application is easy to use. All you need is the location of a study area you are interested in.

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Tutorials for Web GISChangeMatters

References and Reading Esri Products: Landsat Imagery

http://www.esri.com/software/landsat-imagery/ ChangeMatters Viewer

http://www.esri.com/software/landsat-imagery/viewer USGS: View Land Features

http://landsat.usgs.gov/gallery_view.php?category=greenflag&thesort=pictureId Landsat image services now available on ArcGIS Online

http://blogs.esri.com/esri/arcgis/2011/05/10/landsat-image-services-now-available-on-arcgis-online/

Study Historic Landsat Imagery with ChangeMatters Applicationhttp://www.esri.com/news/arcwatch/0811/tip.htm l

Part A: Getting Started

To begin the tutorial, launch the ChangeMatters viewer.

1. Click on or type in this link to open the viewer: http://changematters.esri.com/compare.

2. If this notice appears, read the content, check Don’t show this again and click the x to close the box.

2. Within the Search box, type Aral Sea. From the search results, select Aral Sea.

3. Pixilation, or when individual pixels or squares become apparent on the image, occurs when you zoom in too closely to study area. Use the zoom out icon and click on the image until you can see the full image of the lake and surrounding area clearly (approximately 10 clicks).

The first two panels (from left to right) of the viewer show the area for specific years. The third panel displays vegetation changes over time. Notice that as you pan and zoom around in one panel, the other panels adjust to show the same area at the same time.

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Tutorials for Web GISChangeMatters

Part B: Analyzing Change Over Time

The Aral Sea was once the fourth largest lake in the world, but is now fragmented into a number of smaller water bodies. Landsat imagery can be used to monitor and measure the change of the lake

surface and surrounding lands.

1. Ensure the Select Image Map is set to Infrared and the Select Dates are set to 1975-2000.

2. The first image map on your left is from 1975. Notice also the area the water covers.

3. Next, observe the image map in the centre. This satellite image was taken in 2000.

4. Finally, analyze the last image map to your right which depicts the change over time from 1975 to 2000. Take note of both legends and notice how the water body has diminished in size over the intervening fifteen years and the area of vegetation has increased in size.

Note: The brighter green box on the upper right hand side of the normalized difference vegetation index (NDVI) Change for 1975 to 2000 panel can be mistaken for an increase in vegetation (third panel). However, if you compare it to the 1975 panel you will notice a black rectangle in the same spot. This is the result of missing Landsat satellite image data from 1975 within this area.

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Tutorials for Web GISChangeMatters

5. Change the dates to 1975-2010 and examine the change over time by exploring each image map. If you receive a notice regarding 2005-2010 imagery, read the notification and check the box Don’t show this again.

6. You can also change the Select Image Map to review the territory more thoroughly. Change the Select Dates to a minimum year of 1990 and select a new image map to explore and analyze the vegetation, land and water boundaries and the study area’s natural state.

7. Pan and zoom around the image maps to understand changes in the extent of land cover features that have happened over time. Zoom out to see which countries are adjacent to the Aral Sea.

Part C: Tools and Functionality

1. In the Search box, type Edmonton, Alberta. From the search results that appear, select any option of Edmonton, Alberta, Canada.

2. Ensure that the Select Image Map is set to Infrared and the Select Dates are 1975-2010.

3. Select the View Fullscreen button for the 1975 panel.

4. Use the legend to examine the city. Hover over the thumbnails for more detail.

Note: You can save your image map at any time to your desktop by using the Save map image button. Note 2: On the bottom right hand side, there is a box that describes the type of image map you have selected. Read this information every time you switch to a new image map, it will help you understand what you are viewing.

5. On the top toolbar, select the Swipe tool . The Swipe tool allows you to swipe interactively a layer over the map.

6. In the Swipe tool window, select the layer Infrared and the year 2010.

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Tutorials for Web GISChangeMatters

7. Move the window so you can see the image map clearly by clicking on the window header and dragging it.

8. Next, hover your mouse over the right side of the viewer. You should see a left pointing arrow.

9. Click and drag the arrow towards the left side of the screen to swipe the image map. Here you will see both the 1975 layer and the 2010 layer of Edmonton. Swipe back and forth between the two image maps by dragging the slider.

10. Review the change that Edmonton and it surrounding areas have experienced.

11. Close the Swipe Tool window . Now from the Select Year box in the top right-hand corner, click and drag the button along the bar to 2010.

12. Change the Select Image Map to Natural Color.

13. Select the Swipe Tool once again. Within the Swipe Tool window, ensure the layer is set to Natural Color and the year is 1990. Swipe between the two image maps, zooming in and out.

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Tutorials for Web GISChangeMatters

14. Close the Swipe tool window.

15. Within the map viewer you can also change the underlying basemap from streets (street map), to aerial (imagery), or to topo (topographic) by clicking on one of the three options in the top right-hand corner of the viewer.

To view the changes, you will need to use the Select Transparency tool. Slide the toolbar back and forth to compare the selected image map to the underlying basemaps. You can also change the selected year.

16. Change the Select Image Map back to Infrared and on the right hand side select each year from 1975 to 2010 and notice the gradual change in land cover over time.

17. Using the Overlay Change window to the right of the viewer, check the box and select the date range 1975-2010. Drag the Transparency bar to 50%.

Here you can see the change over time as the top layer within the viewer. Notice the legend once again and how the magenta displays the extent of vegetation decrease.

18. Select Adjust Change Map within the Overlay Change window to note the areas of change in square miles or square kilometers.

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19. Lastly, in the top right hand corner of the viewer, click the button labeled . Doing this will launch the viewer back to comparing image maps in the form of panels, displaying the two years from the chosen date range and the change over time.

Note: When you do this you will lose your previous location and will have to use the search function again to return to a specified area.

Future Considerations To visualize and assess further impacts to the environment over time using the ChangeMatters viewer, complete the following lesson packs:

1. ChangeMatters: Three Gorges Dam http://www.esri.ca/en/content/changematters-three-gorges-dam2. ChangeMatters: Focus on Alberta http://www.esri.ca/en/content/changematters-focus-alberta3. ChangeMatters: Mount St. Helens http://www.esri.ca/en/content/changematters-mount-st-helens

© 2013 Esri Canada. All rights reserved. Trademarks provided under license from Environmental Systems Research Institute Inc. Other product and company names mentioned herein may be trademarks or registered trademarks of their respective owners. Errors and omissions excepted.

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