PostGIS – How to Find Out Direction in PostGIS

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I want to find out the direction from the 2 points from postGIS database. Please see the attached image. I want to find out the direction from the mainPt to any point. But want to get the result as NW, NE, SE or SW. Simply if I get the degree of the angle it can easily be solved.

Thanks enter image description here

Best Answer

You could use ST_Azimuth for that : http://postgis.net/docs/ST_Azimuth.html

This will give you an angle in radians and the 0 rad angle stands for a point in the north of your main point

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[GIS] PostGIS – incorrect result distance between two points

One degree does not "equal 111km" in generality.

select st_distance(
  'POINT(71.2087 45.2714)'::geography, 
  'POINT(66.39 42.3739)'::geography) AS d;

select st_distance_spheroid(
  'SRID=4326;POINT(71.2087 45.2714)'::geometry, 
  'SRID=4326;POINT(66.39 42.3739)'::geometry,
  'SPHEROID["WGS 84",6378137,298.257223563]') AS d;

[GIS] How to find Shortest Route between two points in PostGIS without using pgRouting

You can get the shortest route between two points using PostGIS with ST_Distance (if you want to know the distance) or with ST_MakeLine (for the geometry):

If you want to use the network for routing, then you need a network topology. You could try something like pggraph, but source and target attributes are required as well.

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[GIS] PostGIS – incorrect result distance between two points

[GIS] How to find Shortest Route between two points in PostGIS without using pgRouting

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