Download presentation
Presentation is loading. Please wait.
1
GIS A geographic information system
2
A GIS is most often associated with a map. A GIS is most often associated with a map. The map is a display of a data base in map form The map is a display of a data base in map form The data base is A relational database that groups data using common attributes found in the data set The data base is A relational database that groups data using common attributes found in the data set
3
Example presented the data to the user as relations ( a collection of tables with each table consisting of a set of rows and columns, with each flat table have a common row.) presented the data to the user as relations ( a collection of tables with each table consisting of a set of rows and columns, with each flat table have a common row.) provided relational operators to manipulate the data in tabular form provided relational operators to manipulate the data in tabular form
4
relational database have a location or area associated with the value. relational database have a location or area associated with the value. The area can be raster position which is a square or a given area on a map The area can be raster position which is a square or a given area on a map The area can be a shape area defined by a polygon. The area can be a shape area defined by a polygon.
5
Grass a raster data base (free) http://grass.itc.it/ Grass a raster data base (free) http://grass.itc.it/ http://grass.itc.it/
6
Raster
7
ARC View (polygon)
8
Awhere is a limited version of GIS learning curve only 4 hr. Awhere is a limited version of GIS learning curve only 4 hr. Associated with each data base file is a shape file that contains the shape of the polygon for each element in the data base.
9
Shape files and attribute files for new mexico are available at Shape files and attribute files for new mexico are available at http://rgis.unm.edu/clearinghouse.cfm http://rgis.unm.edu/clearinghouse.cfm http://rgis.unm.edu/clearinghouse.cfm
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.