Postgis ST_DWithin匹配特定半径AND右边的点

Question

I'm using postgis 9.1 and rgeo to develop an map application.

One of the features implies that I find all points that are XXX kms from the current point, and are also on the right of the Point.

I tried with the following query:

Environment.where{ st_dwithin(location, factory.point(170.0, 0), 300000 ) }.where('ST_X(location::geometry) > 170')

The corresponding SQL for the query: [EDITED] SELECT "environments".* FROM "environments" WHERE (st_dwithin("environments"."location", ST_PointFromText('POINT(170 0)', 4326), 300000)) AND (ST_X(location::geometry) > 170 );

Here I hardcoded the point to be in the 170 longitude.

The problem with this is that I can't match points in the [-170,-180] longitudes.

Is there a way to solve this using only postgis functions?

[EDIT] This is a around the world problem with postgis. In this application I'm allowed only to find points to the right and in a certain range.. I can't find a solution with pure SQL...

Thanks!

Answer 1

Consider using the geography type rather than the geometry type.

• What are the pros and cons of PostGIS geography and geometry types?
• Introduction to PostGIS: Section 17: Geography