GTECH 709 Geographic data Geo-relational principle - again Geographic data organization Back to the map
What is Geographic Data? Following the geo-relational principle, geographic data has to have A locational reference Check for yourself about all the different ways we can specify a location Data that describes what can be found at that location: Income, temperature, party affiliation, soil type, etc.
Geographic Data Organization We will have whole sessions on this Location and attributes in one file Latitude Longtitude Precision Address City State ZIP Name Description 51.514 -0.0936 109 Cheapside London UK EC2V 6 GIS Cloud Web-based GIS 38.967 -77.380 555 Grove St Herndon VA 20170 Juice Analytics Data analysis 37.416 -122.02 701 First Ave Sunnyvale CA 94089 Yahoo Address matching 37.423 -122.08 1600 Amphitheater Pkwy Mountain View 94043 Google Google Earth 47.643 -122.13 Street One Microsoft Way Redmond WA 98052 Microsoft Excel 41.132 -73.704 1 New Orchard Rd Armonk NY 10504 IBM You tell me
Geographic Data Organization Location and attributes in multiple files ESRI “shapefile” A collection of .shp, .dbf, .shx files Location and attributes in a database (file) ESRI geodatabases PostGIS database Web services
Back to the Map A digital map is a set of instructions on how to arrange visual representations of geography Items such as a Google map or a satellite image may serve as context We can turn map layers on or off Label map elements Change appearances