0
votes
3answers
111 views

ST_transform postgis

SQL within that zone is a point SELECT "public".zona.zts FROM "public".zona WHERE ST_Within ( ST_Transform ( ST_GeomFromText ( 'POINT(-30.033514 ...
3
votes
1answer
564 views

Routing with multiple points

I am using postgreSQL, postGIS and pgrouting. Now I am really confused on how am I going to find the shortest path between multiple points. I know how to find it between two points through dijkstra ...
2
votes
1answer
130 views

St_buffer width issues

I am using postgres with postgis for spatial data and ArcGIS for visualisation. I am really confused regarding what units the st buffer function uses because when I insert just the value 1 as ...
5
votes
1answer
133 views

Looking for open-source solution to show map with massive objects(3x3 polygon) on a web site

I don't have much experiance in GIS systems. I am developing a web site which need to show a map with 3m x 3m rectangles for a radius of about 400 meters.(about 58,000 polygons for one location) I ...
10
votes
1answer
940 views

Can you query overlapping user-defined polygons at a given point in Google Maps?

I need to find out the limitation of working with the Google Maps API, and the possible solutions for doing semi-complex spatial comparisons. What I'm looking to achieve is a system of comparison ...
12
votes
5answers
993 views

Quality of free geodata compared to commercial sources

What are the sources of excellent geo-location data as possessed by Google Maps ? I am wondering that, even with large amount of volunteer work involved, why is OSM data not comparable to theirs in ...