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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.