1. WHAT IS GIS? By Okan Fistikoglu

2. DEFINITION Geographical Information Systems (GIS) are the systems that store, retrieve, analyze, transform and display geo-coded spatial and attribute data. What is geo-coded data?

3. GEOCODED DATA =Geodata Position (x,y,z) Shape Type (Point, Line, Polygon) Relation to others (Topology) Thematic Content (Indicated Info) SPATIAL DATA ATTRIBUTE DATA

4. GEOCODED DATA =Geodata more examples?

5. COMPONENTS OF A GIS Geographical Information Systems have three important components, 1. computer- hardware 2. sets of application software modules 3. a proper organizational context. These three components must be in balance if the system is to function satisfactorily.

6. COMPONENT-1 computer- hardware DIGITIZER SCANNER C.P.U. DISC DRIVER PLOTTER SCREEN TAPE DRIVER

7. COMPONENT-2 application software The software package for geographical information system consists of five basic technical modules. Data Input Query Input Geo Database Display and Reporting Transformations

8. COMPONENT-2 application software Data Input Query Input Geo Database Display and Reporting Transformations Existing mapsObservations Sensors Magnetic media Interactive terminal Text files Digitizers Scanners DATA INPUT

9. COMPONENT-2 application software Data Input Query Input Geo Database Display and Reporting Transformations GEOGRAPHIC DATABASE Position TopologyAttributes Management System Input Query Input Retrieval Transinformation

10. COMPONENT-2 application software Data Input Query Input Geo Database Display and Reporting Transformations MAPS TABLESFIGURES Magnetic media Visual Display terminal Plotter Printer DISPLAY AND REPORTING

11. COMPONENT-2 application software Data Input Query Input Geo Database Display and Reporting Transformations TRANSFORMATION Maintenance Utilization and Analysis

12. COMPONENT-3 organizational contex Management Aims and Queries from management Information for Management Geographical Information System Data Gathering

13. TYPE OF GEODATA Position (x,y,z) Shape Type (Point, Line, Polygon) Relation to others (Topology) Thematic Content (Indicated Info) SPATIAL DATA ATTRIBUTE DATA REMEMBER!!!

14. ATTRIBUTE DATA (Thematic Content) Alfanumeric Value (String) =  “Okan Fistikoglu” “1. Kordon Street” “Forest” Numeric Value  ≤ ≥       Birth “1971” No. “256” Percent “35” Type Permisible Operations Examples

15. SPATIAL DATA X, Y, Z coordinates of the dataPosition Shape Topology Types Point, Line, Polygon Positional relation of the data to the others Vector, Raster NEW

16. STRUCTURE OF SPATIAL DATA Analysis of attributes and their interactions within the region investigated can be performed using two different approaches. These two approaches determine the process of data collection, data manipulation, and consequently, determine the Structure of Spatial Data. Accordingly, there are two types of structures: (a)vector structure (b)raster or grid structure. VECTOR RASTER

17. VECTOR STRUCTURE X COORDINATE Y COORDINATE ATTRIBUTE 1 ATTRIBUTE 2 35.245856.8459WELL30m POINT X Y

18. VECTOR STRUCTURE 1 2 3 NODEXY 115.2435.48 262.2716.85 3106.3641.78 4110.4732.91 4 LINEFROM NODE TO NODE ATTRIBUTE 11250m 223 32420m

19. VECTOR STRUCTURE 1 2 3 NODEXY 115.2435.48 262.2716.85 3106.3641.78 4110.4732.91 4 LINEFROM NODE TO NODE LEFT POLY RIGHT POLY 11210 22312 32420 41301 53402 1 2 0 ATTRIBUTE 0URBAN 1PARK 2HOUSE

20. RASTER STRUCTURE POINT LINE POLYGON 00000000 00300000 00000000 00000000 00400000 04040000 40004444 00000000 00000000 00440500 04445550 44405500 3=WELL 4=ROAD WIDTH 4=FOREST 5=URBAN

21. VECTOR vs RASTER Some major strengths and limits of vector and raster structures. VECTORRASTER Storage efficiency goodpoor Storage data structure complexsimple Spatial sampling varying across study arearegular across study area Spatial measures preciseapproximate Spatial relationships complex to handleeasy to handle Multi-attribute analysis complexsimple