Intro to Geographic Information Systems (GIS)

Advanced GIS Functions

- proximity selections - Buffers - select top polluting companies and show the number of schools within 2 miles of these companies

Raster Data

- stored ELECTRONIC IMAGE or PICTURE taken as an aerial photograph or satellite image - composed of a rectangular array of square cells, called pixels, with a number in each cell representing the solid color fill of that cell

Geographic Information Systems (GIS)

- computerized systems designed for the storage, retrieval, and analysis of geographically referenced data

Unique Capabilities of GIS

- GIS stores related geographic features in separate collections of files called MAP LAYERS - Map layers can be reused easily and assembled into any number of map compositions and overlaid for analysis

How Does GIS Work?

- GIS uses advanced analytical tools to explore at a scientific level the spatial relationships, patterns, and processes of cultural, biological, demographic, economic, geographic, and physical phenomena

Tools for GIS

- Hardware: Computer, Digitizer, Scanner, Printer/Plotter - Software: Desktop GIS, Internet GIS, CAD Software, Database software - Multimedia: photos, videos, 3D models, WWW - GIS Personnel

GIS Example

- Identify polluting companies and their proximity to populations in poverty, water features, or schools. 1. Start with: databases & map layers 2. Add additional map layers: political features (municipalities), physical features (lakes, rivers, etc.), Administrative data (schools) 3. Maps & tables are INTERACTIVE

Vector Data

- Map Features: points, lines, polygons - Feature Attributes: every feature has attributes (name, area, population)

Scale of GIS data

- global to local

GIS Answers the Following Questions...

1. Location: What is at...? Where is it? 2. Condition: Status of features? 3. Trends: What has changed since...? 4. Patterns: What spatial patterns exist? 5. Modeling: What if....?