Tagged Questions
14
votes
7answers
5k views
Nearest neighbor between a point layer and a line layer
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 ...
5
votes
2answers
2k views
How to convert PostGIS table to Shapefile in Python?
I want to convert a PostGIS table into a shapefile (without using pgsql2shp).
In order to create a geometry in the shapefile I have to give the Xmin,Ymin and Xmax,Ymax, and the geometry which I have ...
9
votes
3answers
1k views
How to populate an undirected graph from PostGIS?
This question is more related to resources that I might not have identified yet, although I've been searching the web for a while.
In the project I'm working at the moment I need to run a ...
3
votes
3answers
2k views
Writing a plugin for Qgis using python to access PostGIS and write geometries
Sorry about the strange title didn't really know how to word it.
I currently use MapInfo to do most of my GIS work however I have recently installed PostGIS 1.5 and am really liking it so far. A ...
2
votes
2answers
770 views
Automating batch load of multiple GPX files into PostGIS
I've got 50+ GPX files that I would like to "batch load" into a PostGIS database. All of the track_points data would be loaded into a "track_points" table (with typical GPS fields like lat, long, ...
7
votes
2answers
416 views
How to catch PostgreSQL/PostGIS errors in GDAL/OGR Python bindings?
Is it possible to catch PostgreSQL output error messages in OGR after a query has failed?
For example
conn.ExecuteSQL('SELECT * FROM non_existing_table;')
In Postgres this returns an error ...
2
votes
1answer
424 views
How to debug 'Layer is not valid error' from Python plugin?
I'm trying to understand what goes wrong with a QGIS python plugin.
Basically I'm trying to render a series of POINT.
The query works fine, at least giving it by hand from inside PostGIS DB:
"SELECT ...
5
votes
1answer
313 views
How to interpolate polyline or line from points?
We have a lot of points, but with no timestamps to create ways. For now, I've created a sample of the way the points traverse. It's in here, this way can be compared with a Google one.
I haven't ...
3
votes
1answer
595 views
How to save a newly created shapefile in PostGIS?
I am creating shapefile using shapefile.py and my database has records more that 65k which is the limit of the shapefile. How can I create shapefiles then?
Is it possible that somehow I am able to ...
2
votes
1answer
366 views
The minimum bounding circle of geometry that crosses the 180th meridian
Background: I've been given a task where I have to calculate the minimum bounding circle of Alaska (for the purpose of running a Roeck test). I'm using the Census' state level geometries available ...
2
votes
2answers
299 views
unable to call shp2pgsql using python
I am unable to call shp2pgsql using python as I have to pass various options like (-s -a -i)
and I am not getting the required output ..
Method I am using is
p1 = subprocess.Popen(["cmd", "/C", ...
-2
votes
1answer
218 views
QGIS and Python - create line with multiple points in postgis [closed]
How can I create a line, with Python functions, with many points that are records in Postgis?
Thank you
