The first task in Chapter 8, Spatial Analysis in QGIS was to select every house which is at least 200 meters away from busy roads and 500 meters away from industrial areas. To complete this task, we created buffer zones around the problematic features and areas, calculated their union, and selected every disjoint house. Following the same approach, we can use two functions of PostGIS--ST_Intersects and ST_Buffer. We do not have to discuss ST_Intersects again, as we have already used it several times. ST_Buffer, on the other hand, is a different function. It does not act as a filtering function, but it creates and returns new geometries based on the input geometries and buffer distances. To buffer the busy roads ...
Proximity analysis in PostGIS
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