2
votes
1answer
54 views

How to make a good table or view for QGIS in PostGIS?

I have a PostGIS db from OpenStreetMap (osm2pgsql) with my custom table. There are two problems with it: When I list tables, the columns from my table are scanned for geometry type, and it takes ...
0
votes
1answer
67 views

pgRouting:routing problems using reverse_cost

I saw this post:Routing issues with pgrouting, and try the ability of reverse_cost. As the result of this post, if there is only one way to go from one node to another, even though the reverse_cost ...
0
votes
1answer
103 views

Can pgRouting work more efficiently?

I use a river network on which has a lot of nodes to test pgRouting, and I run the SQL, searching for the shortest path between nodes. SELECT * FROM shortest_path(' SELECT gid as id, ...
1
vote
1answer
138 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 ...
2
votes
1answer
448 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 ...
8
votes
1answer
377 views

How to split two interscting polygons by the average linestring of the shared area (QGIS / python shapely)

I have two polygons, POLYGON((-5 -5,-5 5,5 5,5 -5,-5 -5)) POLYGON((1 1, 1 7, 7 7, 7 1, 1 1)) and wish to split them evenly. The result should be a split along the red marked line. I'm using ...
5
votes
2answers
3k views

how to create a new postgis database for usage with QGIS under windows

After installing postgresql with postgis under windows xp I have 3 databases: postgis postgres template_postgis now I try to create a new spatially enabled database in pgAdminIII: I select ...