2. What is GIS Geographic Information Systems –System capable of capturing, storing, analyzing, and displaying geographical data identified according to location Uses include: Topological modeling, simulating environmental effects, graphical display, climate history

3. How GIS Works Reference system using latitude and longitude (spatial data) to pin point global locations Envision the geographic aspects of a body of data Converts data points into 3D image map consisting of layers that show elevation and land form http://ci.ftlaud.fl.us/GIS/images/learn2.gif

4. GIS Samples Map of lava flows along Mauna Loa's northeast rift zone Cat Mountain in Arizona http://erg.usgs.gov/isb/pubs/gis_poster/ http://hvo.wr.usgs.gov/volunteer/gis/maunaloa-gis_large.jpg

5. Relationship to Data Structures Uses grid/graph data structures to store data Network represented by adjacency matrix where rows and columns are location nodes Arc relationship represented on table Data is displayed in graphical form http://www.npwrc.usgs.gov/resource/habitat/research/struct.htm

6. Familiar Algorithms Shortest path: –The labeling method employs a scanning operation to scan each node recursively until all nodes on a network are scanned onto the map –Time complexity O(N 2 ) http://www.osa-jon.org/images_issues/jon-3-11.gif

7. Familiar Algorithms Cont’d Adjacency lists used to show relationship between location nodes on graph –Time complexity O(N 2 ) –N = number of nodes used in graph “Divide and Conquer” –Nodes are divided into smaller and small groups –Intersection tests used to determine relationship between two nodes on graph

8. Conclusion GIS technology utilizes adjacency matrices and lists to create topological maps Data points are nodes showing true land features End result is conversion of data points into 3D image http://www.sgi.com/fun/gallery/images/gis.jpg

9. References Images http://erg.usgs.gov/isb/pubs/gis_poster/ http://ci.ftlaud.fl.us/GIS/images/learn2.gif http://hvo.wr.usgs.gov/volunteer/gis/maunaloa-gis_large.jpg http://www.osa-jon.org/images_issues/jon-3-11.gif http://www.sgi.com/fun/gallery/images/gis.jpg Information http://erg.usgs.gov/isb/pubs/gis_poster/ http://www.rac.louisiana.edu/education_tools/gis.html http://www.ncgia.ucsb.edu/giscc/units/u064/u064.html http://www.coloradocollege.edu/dept/SW/GIS_Lab/tips&tricks/Under standing_Topology.dochttp://www.coloradocollege.edu/dept/SW/GIS_Lab/tips&tricks/Under standing_Topology.doc http://www.npwrc.usgs.gov/resource/habitat/research/struct.htm