Tagged Questions
1
vote
1answer
51 views
pgRouting：how to use reverse_cost？
I add a new column, naming it "reverse_cost", and give it the same data in the shape_leng column.
But as I run the shortest path algorithm in pgadmin, I got an error message.
here's my sql code
...
0
votes
2answers
61 views
How to create a new column to store the length of a linestring in postgis?
I am working with pgRouting, following this nice guide：A Beginner’s Guide to pgRouting
I am now in this step：Calculating shortest routes, with these codes below
SELECT * FROM shortest_path('
SELECT ...
1
vote
0answers
102 views
Function for Selecting Points in a Polygon
I've been banging on this for a few hours, but since I'm relatively new to PostgreSQL and PostGIS, I can't find the solution. I'm trying to create a stored procedure (function) which will return all ...
2
votes
1answer
130 views
generate height data from DTED maps
I have 16 DTED maps of (1 degree x 1 degree). I have to generate combined height matrix of maximum 4 (1 degree x 1 degree) DTED maps in my C++ application.
Can someone suggest to me which open source ...
2
votes
3answers
124 views
ST_Covers: Geography Implementation is not working, Geometry Implementation taking too long
I have a query: (This query uses geographical implementation of ST_Covers function)
SELECT ST_Covers(ST_GeoGraphyFromText('MULTIPOLYGON(((179 -89,179 89,-179 89,-179 -89,179 ...
2
votes
2answers
375 views
raster2pgsql part of PostGIS?
Hi GIS Stackoverflow people,
I wanted to use the PostGIS functionality [raster2pgsql][1], but I had to discover that the Python function was not installed with my PostGIS installation.
Do you know ...
2
votes
1answer
293 views
How to relate Non-Spatial table to Spatial table in two different Postgis DBs?
I need to relate a Non-spatial table to Spatial table, but both are in different database.
Spatial_table(dbname:dist)
gid
district_name
district_code
geom
Non_Spatial(dbname:census)
ID
...
3
votes
0answers
264 views
How can I properly add PostGIS data into MapGuide Maestro?
I am having trouble connecting a PostGIS database to MapGuide Maestro. Actually, I have added the PostGIS data into Maestro, but when I click to validate the layer it shows an error message:
...
4
votes
1answer
211 views
Self-intersecting polygon using extreme values
I have this polygon
POLYGON((1.2E-15 1.1E-15,1.31E-15 1.21E-15,-180 -90,180 90,1.2E-15 1.1E-15))
It uses an extreme coordinates like (1.2E-15 1.1E-15) and (180 90)
When I call ST_isValidReason, ...
3
votes
2answers
175 views
Invoke PostGIS functions outside of the database? Need to force 3D in GeoDjango
I'm looking to ensure that all geometries saved to the database are three-dimensional. It's easy enough to do with a call to the database,
select ST_Force_3D( ST_GeomFromText( blah blah ) )
...but ...
5
votes
2answers
1k views
Can't import OSM data to PostGIS, permission denied
I use Postgres 9.1 on Xubuntu 11.10. I've created a db 'aus' and user 'aus', granted ALL on the db to the user. Now I try to import the data, and it outputs this error:
$ osm2pgsql --create ...
7
votes
2answers
1k views
PostGIS ST_Buffer Radius Help
I am trying to find all points within a five-mile radius of a given point. I have a query like this:
SELECT * FROM table WHERE ST_Contains(ST_Buffer(geomFromText('POINT(0 0)', 4326), ?), latlon)
I ...
5
votes
2answers
466 views
Creating a spatial PostGIS table as a result of a PostGIS query
When I want to store the results of a spatial query as another PostGIS table, what should I do? I am interested in identifying all residential buildings that fall within a set of parcels:
CREATE ...
2
votes
3answers
674 views
Inserting polygon centroids into an additional column in PostGIS
I'm trying to calculate the x and y centroids for a table using ST_Centroid. The documentation says that it returns the geometric center of a geometry. I first made a column X:
ALTER TABLE ...
4
votes
1answer
531 views
Geodjango distance between two points appears incorrect
I want to show you something. I am using django+postgis and I am experiencing wrong distance values between two points.
This is my model:
class Location(models.Model):
name = ...
4
votes
2answers
300 views
Does PostGIS not work with psql?
I have a sql script that creates several tables, a trigger, and a trigger function. All the commands work in pgAdmin when I execute them in the "Query" section. My goal is to put all these commands ...
8
votes
4answers
2k views
How to create a circle in PostGIS?
I'm using PostGIS 1.5.2, with geometries in SRID:900913.
I need create a circles using a list of points as centre, with a radius of 600 kilometers.
I'm using this query:
INSERT INTO circles (geom) (
...
6
votes
1answer
1k views
How to measure length of line accurately?
In postgis 1.5 for the below given query the answer is 1540651.62674101 meters ,
SELECT ST_Length(ST_GeomFromText('LINESTRING(77.83042478941326
9.98463896136159,78.03469506809812 23.90398909552571 ...
8
votes
2answers
551 views
Splitting polylines using regions with PostGIS
I was wondering if it is possible to split a polyline on polygon boundaries (regions) in PostGIS, the picture below is of what we have at the moment and showing where I need the polylines split:
...
