The Geo project actually contains three modules:
- Geo - provides an API for storing/retriving spatial data for PostgreSQL and MySQL spatial fields
- Geo Field - provides CCK integration for storage and display of native spatial data, using the Geo API
- Geo Data - provides the ability to import and query ESRI shape files
What are the advantages of the Geo module over other Drupal GIS solutions?
* stores GIS data in native form using spatial extensions on MySql and PostgreSQL (Oracle and SQLLite also have spatial extensions, but are not yet implemented in the Geo module)
* the spatial extensions allow you to do math on GIS data
* is a point within a polygon?
* do two linestrings intersect?
* find the area of a polygon
* PostgreSQL has a much fuller set of GIS functions than MySql.
* If you're doing anything "serious", use PostgreSQL.
* examples?
* can store points, linestrings, and polygons
* What is Geo module?
* CCK and Views required for most cases
* terminology
* shape files
* point
* linestring
* polygon
* WKT (well known text) - http://en.wikipedia.org/wiki/Well_Known_Text
* POINT(x y)
* format is POINT(lat lon)
* sample point (Washington, D.C.): POINT(37.0625 -95.677068)
* LINESTRING(point1, point2, point3, ...)
* format is LINESTRING(lat lon, lat lon, lat lon, ...)
* sample linestring (track from Washington D.C. to N.Y.): LINESTRING(38.925 -77.003,39.300 -76.5855,39.968 -75.102,40.755 -73.981)
* POLYGON((point1, point2, point3, point1), (point4, point5, point6, point4)) (outer boundry, inner boundry, ...)
* format is POLYGON((lat lon, lat lon, ...))
* sample polygon (portion of the Washington D.C. beltway): POLYGON((39.020 -77.106,39.021 -76.971,39.002 -76.890,38.950 -76.865,38.900 -76.847,38.847 -76.861,39.020 -77.106))
* WKB (well known binary)
* GIS resource links
* http://www.opengeospatial.org - organization for setting up GIS standards
* sample use cases
* examples...
