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Introduction to GIS

Introduction to GIS. 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. What is GIS?. Geographic Information System

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Introduction to GIS

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  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

  9. Features as Raster Data

  10. Resolutions

  11. Resolutions

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

  13. 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

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

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

  16. 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

  17. 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

  18. 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)

  19. Introduction to ArcMap

  20. 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…

  21. Geoprocessing Tools

  22. 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/

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