geographic information system for egyptian railway system(gis)
Post on 14-Jun-2015
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Geographic Information System (GIS)Eng. Ismail El Gayar
What Is GIS??
• Is any system that captures, stores, analyzes, manages, and presents data that are linked to location.
• is the merging of cartography and database technology
Geographical Information System Modules
• Database• Map information• Computer-based link between them
This technology has developed from:– Digital cartography and CAD– Data Base Management Systems
Geographical Information System
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ATTRIBID X,Y123
ID123
CAD System Data Base Management System
Geographical Information System
DigitalMapping
Photo-grammetry
ComputerAided
Design
Surveying
RemoteSensing
Databases
GIS
Cross-disciplinary nature of GIS
Geographical Information Systemcomponents
Specific applications /
decision making objectives
?G I S
Spatial
data
Computer hardware /
software tools
What makes data spatial?
PlacenameGrid co-ordinate
Postcode
Distance & bearingDescription
Latitude / Longitude
Characteristics of spatial data
• Location
• Description: Kingston University,PenrhynRoad Centre
• Post Code: KT1 2EE• Grid Reference: 518106.72
168530.37• Latitude/Longitude: 0° 21’ 55.38”W, 49° 36’
17.62”N
• Input & update spatial information
• Data conversion
• Storage & management of information
• Manipulation of spatial data
• Analysis of spatial information
• Presentation of data
System Process Flow
GIS Structure
GeographicDatabase
Data Input
Transformationand Analysis
Query
Output: Display
Co-Ordinate System
• A co-ordinate system is a standardized method for assigning codes to locations so that locations can be found using the codes alone.
Other GIS Features
Real world is continuous– Infinite number of places exist– Coordinate system may be used to definelocations– Geographical variation may be described byvariables (or attributes)⇒Population density
⇒ Elevation⇒Temperature• Attribute may be conceptualized as a field– Each field represents the variation ofattribute over the surface of the earth
Field View
Referencing the Field{a, x, y, z, t}
a = attribute (empirically confirmable)(tag)
x,y,z = spatial coordinates
t = reference to time
Field View
Database Management System
DBMS Components
• Data model• Data input• Indexing – data structure• Query language• Security (controlled access)• Controlled update• Backup and recovery• Standard operations, data manipulation,administrative tools• Programmable interface - customization
DBMS Types
• Tabular (flat file)• Hierarchical• Network• Relational• Object• Object-relational• Deductive
GIS Based Functionality
• Layers of information – data integration• Visual inspection• Query• Buffering – regular and irregular• Overlay• Areal interpolation
GIS is a part of Decision Making process
Other GIS Features• Produce good cartographic products(translation = maps)• Generate and maintain metadata• Use and share geo-processing models• Managing data in a geodatabaseusing data models for each sector
Databases & GIS
• At a simple level a GIS may just form the graphical interface to a database
• The majority of GIS applications follow this example
Linked database table
Spatial data
SQL Query Manager
MapInfo
Buffering
• Creation of an area of interest around an object– proximity analysis and environmental impact assessment.
GIS Provide Data Integration
Example:- Roads- Population- Hospitals- Wells- Mines
Spatial Image
• Information referenced by its location in space
Data Representation
Raster Image
Vector Image
Real World
Spatial data storage
•Vector model
•Raster model
point
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4,1
7,105,9
4,7
6,68,6
9,8
line
polygon
2,2
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as geometric objects: points, lines, polygons
as image files composed of grid-cells (pixels)
A Desktop GIS should be able to handle bothtypes of data effectively!
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The benefits of GIS include:
• Better information management
• Higher quality analysis
• Ability to carry out “what if?” scenarios
• Improve project efficiency
GIS Softwares
• ArcGIS• ArcView• AutoCAD MAP• UNIX GIS• GRASS
Arc GIS
Thanks for your time
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