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 Jul 10 comment Optimizing a nearest neighbor calculation using PostGIS Thanks for the encouragement! Successfully using v1.5.2 Jul 10 comment Optimizing a nearest neighbor calculation using PostGIS Do you know if the line `WHERE ST_DWithin(a.the_geom, b.the_geom, 400)` will prevent distances greater then `400` to be calculated or just recorded? Also, can a case statement be used for numerical calculations? for example: `CASE WHEN ST_DWithin(a.the_geom, b.the_geom, 400) == TRUE THEN ST_DWithin(a.the_geom, b.the_geom)` Jul 8 comment Nearest Neighbor calculation in PostGIS I thought this would only not record the values above a certain level, but that it would still calculate them. Hence my subsequent question....gis.stackexchange.com/q/11979/803 Jul 8 revised Optimizing a nearest neighbor calculation using PostGIS added 621 characters in body Jul 8 comment Optimizing a nearest neighbor calculation using PostGIS Thanks for the suggestions Nicklas; as I've found it tricky to get pgAdmin/PostGIS up and running I think I will avoid using 1.5 at the moment. It seems like ST_Dwithin() is a way to solve this. Jul 8 asked Optimizing a nearest neighbor calculation using PostGIS Jul 8 comment Nearest Neighbor calculation in PostGIS Thanks for your answer Mike. I used it, and now understand what is going on. Maybe I should ask this as a new question, but is there a way of optimizing the calculation? For example if I have 100 polygons that is 10,000 calculations. I happen to have 1,000,000 polygons and am wondering how to scale down the calculation. Jul 8 comment arcpy taking longer and longer in a loop I agree with @blord - where your `del row` is now, it just deletes the last row, rather than each iteration of the loop. Jul 7 accepted How do you cite ArcGIS? Jul 7 comment Error importing Shapefile to PostGIS using Importer GUI I'm not certain what I was doing wrong previously, but I followed the steps here: workshops.opengeo.org/stack-intro/postgis.html and managed to import data succesfully. Jul 7 asked Nearest Neighbor calculation in PostGIS Jul 7 comment Finding minimum edge to edge distance of polygons using ArcGIS Desktop? @Paul I just tried using QGIS to load data from a PostGIS database. There is a SQL query builder in it; do you know how I would run your code using this structure? Jul 7 comment Error importing Shapefile to PostGIS using Importer GUI When I try the line `\i /usr/share/pgsql/contrib/postgis-1.5/postgis.sql;` I get the error message 'No such file or directory'. Where can I check if this exists? I'm not sure if it makes a difference that I'm using windows. I was able to run the two `GRANT` lines. Jul 7 revised Error importing Shapefile to PostGIS using Importer GUI added 10 characters in body Jul 7 revised Error importing Shapefile to PostGIS using Importer GUI added 968 characters in body Jul 6 comment Error importing Shapefile to PostGIS using Importer GUI it seems that `geography()` is not a term I can use in my import query. How can I check if I installed all the postgis parts correctly? Jul 6 revised Where to get raster files of Earth, united states added 119 characters in body Jul 6 answered Where to get raster files of Earth, united states Jul 6 comment Error importing Shapefile to PostGIS using Importer GUI I did tick this box - I'm using PostGIS 1.5.2 so I assume it is an error on my part. I was able to import a shapefile when I choose just to import the attributes. Jul 6 comment Error importing Shapefile to PostGIS using Importer GUI Should I be using a different Column Geometry to `geog`? I'm not familiar with the different types.