Geographic Information Systems Patty McGray University of Phoenix EDTC 560 Applications of Multimedia and Web Page Design Janet Wright November 17, 2004

What is a GIS? An integration of five components

GIS functions Query Analyze Store Display Capture Output Buildings Streets Reality Customers

Capturing data GIS Data GPS , , , , , , , , , , Coordinates Hardcopy maps Digital data

Storing vector data Real-world entities are abstracted into three basic shapes Points Retail stores Lines Streets Areas/Polygons Land uses

Storing raster data Use square cells to model reality Each square holds a value e.g. Photographs, TV Reality (A highway) X,Y Rows Columns

Query Identifying specific features Identifying features based on conditions Florida counties with a population greater than 300,000

Analysis Which parcels are within 50 feet of the road? Well type Drilled Building owner Smith Soil type Sandy Well type Drilled Building owner Smith Soil type Sandy Proximity Overlay Network

Display Maps Graphs Reports

Output Document Internet Paper map GIS Data Image

Organizing spatial data A GIS works with thematic layers of spatial data Answer questions by comparing different layers of data

Components of data Three general components to geographic information Attributes Geometry Streets Behavior Streets and highways may not intersect Rules: Road name Road type

Using your data The relative position of features determines relationships I-80 connects San Francisco and New York San Francisco is contained by California I-80 has length and direction New York is adjacent to the Atlantic Ocean