Mar

30

Union of two geometries in PostGIS

Filed on March 30th, 2007 at 5:49 pm under , | Comments Off 

For people not familiar with the Spatial SQL, I post this quick sample showing its beauty and simplicity at the same time.
We will go using PostGIS, but this could be performed in a similiar way with any GIS Database compliant with OGC Simple Feature Access - SQL Option.

The geomunion function

The geomunion Open GIS function make it possible to combine two geometries and getting from these a single geometry.

FUNCTION geomunion(geometry, geometry)
  RETURNS geometry

It is very easy to generate a geoprocessed layer from an original layer, making an union of its polygons based on a common attribute.

I will show you how to use the geomunion PostGIS function with a quick sample.

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Mar

21

zigGis 1.2 released

Filed on March 21st, 2007 at 7:44 pm under , , , | 7 Comments 

zigGIS 1.2, the Open Source ArcGis Desktop's connector to PostGIS, has just been released and you can download it here.

ArcMap with PostGis data using zigGis

This is a major release, as far it implements new important features like selections and rendering. At this time editing is still not supported (so it is still a read only connector).
Also ArcMap documents persistence is now fully supported, meaning that you can save your mxd document with your PostGIS layer in them, and then open them again without problems.
zigGis should correctly work with ArcGis 9.0 (sp3), 9.1 and 9.2. Before installing it don't forget to install .NET support for ArcGis.

the ArcMap toc with PostGis data using zigGis

Here is a list of supported and unsupported features in ArcMap with zigGis 1.2:

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