Introduction to GIS

1. Introduction to GIS

2. Goals • Learn what GIS is • Learn some of the basic terminology used in GIS • Learn some of the basic operations and applications of GIS using ArcMap • Learn examples of analyses that can be performed with GIS

3. What is GIS? • Geographic Information System • Describes and characterizes the earth • Visualize and analyze • Models geographic information as a set of layers

4. Types of Data Structures

5. Attributes • Tabular information to describe features • Can include numbers, text, date, time

6. Feature Classes • Vector data • Representation using geometry (vertices)

7. Ag Hall Monroe St. Polyline Feature Polygon Feature Point Feature Bus Stop

8. Raster Datasets • Divides world into discrete cells in a grid • Each cell has a value to represent a characteristic of that location

10. Features as Raster Data

11. Resolutions

12. Resolutions

13. Georeferencing • Assigning spatial locations to map features • Coordinate systems

14. Coordinate Systems & Projections • Arbitrary designations for spatial data • Purpose is to provide a common basis for communication about a place on the earth’s surface • Use of reference datum's • Two types of coordinate systems • Geographic Coordinate Systems • Projected Coordinate Systems

15. Geographic Coordinate Systems • Uses a 3-D spherical surface to define locations on the earth

16. Projected Coordinate Systems • Compresses 3-D surface onto a flat 2-D surface • Spherical coordinates  planar coordinates

17. Projected Coordinate Systems • Has constant lengths, angles, and areas across the two dimensions • Create distortions in some aspect of distance, area, shape, or direction • Users cope by using projections that fit their intended use, geographic location, and extent

18. Datums • Define the position of the spheroid relative to the center of the earth • Provide a frame of reference for measuring locations on the surface of the earth • Define the origin and orientation of latitude and longitude lines

19. Datums • Local datums align their spheroid to closely fit the earth's surface in a particular area • Coordinates of all other points are calculated from origin point (fixed)

20. Introduction to ArcMap

21. Introduction to ArcMap • File types • Tons of files for one layer • .shp, .tif, .gif, .png…. • Metadata • Data about the data • Usually a text file (.txt) • Tells you important information about who created it, when, projection, etc…

24. Geoprocessing Tools

30. Getting GIS Data • USDA-NRCS Geospatial Data Gateway • http://datagateway.nrcs.usda.gov/GDGHome.aspx • Oklahoma State University • http://www.ocgi.okstate.edu/ • University of Oklahoma • http://www.csa.ou.edu/