GIS means Geographic Information System. It is now best for spatial database analysis

1. Geographical InformationGeographical Information
System & Remote SensingSystem & Remote Sensing
(GEO 212)(GEO 212)

2. What we will do?What we will do?
Theoretical background on GIS and RS
Tools and techniques used in GIS/RS
Geospatial analysis using ArcGIS

3. Introduction to GISIntroduction to GIS

4. A GIS is a system
(hardware + database
engine) that is designed
to efficiently, assemble,
store, update, analyze,
manipulate, and display
geographicallygeographically
referenced informationreferenced information
(data identified by their
locations).
++
Information System
Geographic Position
What is GIS?What is GIS?
GIS = Geographic Information System

5. GIS links graphical features (entities) to tabular data
(attributes)
What is GIS?What is GIS?

6. Data can be:
1. Positioned by its known spatial
coordinates
2. Input and organized (generally in layers)
3. Stored and retrieved
4. Analyzed (usually via a Relational DBMS)
5. Modified and displayed
Key Functions of a GISKey Functions of a GIS

7. GIS System and ComponentsGIS System and Components

8. Decision
GISGIS
ProcessProcessOutput
GIS
analysis
Import or
build datasets
Define GIS
criteria
Define
problem
Geographic Information SystemsGeographic Information Systems

9. Representing Spatial ElementsRepresenting Spatial Elements
Raster
Vector
Real World

10. Raster:
Stores images as rows and columns of numbers with a
Digital Value/Number (DN) for each cell.
Units are usually represented as square grid cells that are
uniform in size.
Data is classified as
“continuous” (such as in an
image), or “thematic”
(where each cell denotes a
feature type.
Numerous data formats
(TIFF, GIF, ERDAS.img
Representing Spatial ElementsRepresenting Spatial Elements

11. Vector:
Allows user to specify specific spatial locations and
assumes that geographic space is continuous, not
broken up into discrete grid squares
We store features as sets of X,Y coordinate pairs.
Representing Spatial ElementsRepresenting Spatial Elements

12. Entity RepresentationsEntity Representations
Points - simplest element
Lines (arcs) - set of
connected points
Polygons - set of
connected lines
We typically represent objects in space as three
distinct spatial elements:
We use these three spatial elements to
represent real world features

13. AttributesAttributes
• In the raster data model, the cell
value (Digital Number) is the
attribute. Examples: brightness, rainfall
value, landcover code, SST, etc.
• For vector data, attribute records are
linked to point, line & polygon features.
Vector data can store multiple attributes
per feature. Vector features are linked
to attributes by a unique feature number.

14. Raster vs. VectorRaster vs. Vector
Raster Advantages
1. The most common data format Easy to
perform mathematical and overlay operations
2. Satellite information is easily incorporated
3. Better represents “continuous”- type data
Vector Advantages
1. Accurate positional information that is best for
storing discrete thematic features (e.g., roads,
shorelines, sea-bed features.
2. Compact data storage requirements
3. Can associate unlimited numbers of attributes
with specific features

15. • Data Assembly
• Data Storage
• Spatial Data Analysis
and Manipulation
• Spatial Data Output
GIS FunctionsGIS Functions

16. Data AssemblyData Assembly
Maps
Satellite
Information
Data Transfer
Direct Entry
GPS
Manual Digitizing
Scanning
Database
Data Transfer
Keyboard
Image Processing
Data Extraction
GIS FunctionsGIS Functions

17. GIS StorageGIS Storage
GIS FunctionsGIS Functions
Spatial data
(ARC functions)
Attribute data
(INFO or TABLES functions)
1 (Universe polygon)
2 3
4 5
3
COV# ZONE ZIP
1 0
2 C-19 22060
3 A-4 22061
4 C-22 22060
5 A-5 22057

18. Spatial AnalysisSpatial Analysis
Overlay function creates new “layers” to
solve spatial problems

19. • Tables
• Maps
• Interactive Displays
• 3-D Perspective
View
Spatial Data OutputSpatial Data Output
GIS FunctionsGIS Functions

20. Is GIS about software only?Is GIS about software only?
• A Geographic Information
System is not only about
computers, software and
electronic data.
• A GIS is an organised
collection of :
• Hardware
• Software
• Network
• Data
• Procedures
• And people!

21. Desktop GISDesktop GIS
• A GIS, or GIS software, allows
you to interactively work with
spatial data.
• A desktop GIS is a mapping
software that needs to be
installed onto and runs on a
personal computer.
• In this course, we will use
ArcGIS which is developed by
ESRI.

22. ESRI ArcGIS SystemESRI ArcGIS System
Clients
FilesFiles
(Personal(Personal
Geodatabase,Geodatabase,
Shapefiles, Coverages,Shapefiles, Coverages,
Grids, tins, etc)Grids, tins, etc)
ArcSDE Services
Database storage/access
DatabasesDatabases
Multi-userMulti-user
GeodatabasesGeodatabases
(in Oracle, SQL(in Oracle, SQL
Server,Server,
IBM DBII, etc)IBM DBII, etc)
ArcInfo ArcEditor ArcMap
ArcIMS Services
Map display & query
ArcExplor
er
Browser
ArcPad
ArcEngine/
ArcObjects
Application
Development &
Customization
x: ArcGIS Workstation
Consistent interface
Increasing capability
ArcCatalog
ArcToolbox
ArcCatalog
ArcToolbox
ArcCatalog
ArcToolbox
Source: ESRIHandheld/Wireless
ArcServer Services
Full GIS analysis