I'm learning how to use PostGIS and spatial databases for analysis. What I am trying to do is perform a calculation to get the distance for the nearest polygon in a file, using the edge calculation, ...
I've asked this question several times on stackoverflow and irc between #qgis and #postgis and I also tried to code it or implement it my self in postgis with no real answer. Using programming (most ...
I'm using PostGIS to calculate the nearest neighbors of polygons. What I want to calculate is the minimum distance from each polygon, to the nearest polygon. Thus far I have got great help from Mike ...
I'm trying to use Postgis 2.0 new function <-> (Geometry Distance Centroid) in order to calculate, for each row of my table (cosn1), the distance to the nearest polygon of the same class. I was ...
I've a list of a few hundred cities with their latitude/longitude. Given another location (also in lat/long) I need to find the nearest city. As I don't use any GIS, by now the obvious algorithm is ...
This should have been an obvious precursor (that I didn't ask) to my other question: PostGIS function to create spider diagrams? If I do not know the relationship between a point in layer A (stores) ...
I have a point cloud in my database (SQL Server 2008 spatial). That is about 6 million records. There are 3 columns: id, value, geom. What is the optimal way of getting the 'value' at input lat long?? ...
I have a raster consisting of integer values in each cell. I want to check every adjacent cell in a 3x3 grid to see if any one of the adjacent cells has a value EQUAL to the center cell, and if so, ...
I'm trying to do a nearest neighbour analysis on fish shoals distribution. I go to Vector > Analysis Tools > Nearest neighbour analysis. I choose the appropriate layer and when I hit ok the black ...