So I'm in the middle of learning postgis/postgres. I've a polygon table. I've a point table. The polygon layer contains a foreign key that points to another table. For the example the Foreign key ...
We are looking to map out 'incidents' at schools, but the incident table, which contains a few thousand records, only has a school number (plus the incident data). The table format is an Excel ...
Using QGIS 1.8.0, Postgis 2.1.0, and still new to all that. As the headline points out, I have a list of samples, which are found within areas (no point (GPS) coordinates). With a search query I ...
I am in the process of building a data warehouse in PostGIS, that will store the length of the road network of a country (Lines) per Administrative Area (i.e. Province or State, referred to as AA ...
I have a point dataset representing households that I want to associate with a parcel layer (i.e. assign its parcel_id). With ArcMap, I could spatially join the polygons to the points and specify that ...
I use mapnik to render map with datasources from a postgis database. One query is a join on two table, one with a geometry (a polygon) and the other one with some fields I want to use for rendering. ...
I had a table of road line strings that contained duplicate road names with different geoms for different line segments. I extracted the duplicates to another table. I now want to join these segments ...
What is the right way to calculate the difference between two layers? I tried to use the following approach: SELECT ST_Difference(river.geom, lakes.geom) FROM river LEFT JOIN lakes ON ...