[postgis-users] Transforming Coordinates

[Alan Cunnane]

Hi guys

I have a table with easting northing coordinates and these points in a geom column. I have 15,000 points with an easting and a northing (brittish national grid) and created the geom column using these commands:

SELECT AddGeometryColumn( 'bus_stops1', 'east_north', 27700, 'POINT', 2 );
UPDATE bus_stops1 SET east_north = PointFromText('POINT(' || easting || ' ' || northing || ')',27700);

The table looks like this at the moment:

 easting | northing |                     east_north
---------+----------+----------------------------------------------------
  226965 |   676038 | 0101000020346C000000000000A8B40B41000000008CA12441
  226761 |   675945 | 0101000020346C00000000000048AE0B4100000000D2A02441
  226696 |   675893 | 0101000020346C00000000000040AC0B41000000006AA02441
  226473 |   675777 | 0101000020346C00000000000048A50B4100000000829F2441
  226465 |   675731 | 0101000020346C00000000000008A50B4100000000269F2441
  226614 |   675611 | 0101000020346C000000000000B0A90B4100000000369E2441
  226603 |   675605 | 0101000020346C00000000000058A90B41000000002A9E2441
  226869 |   675621 | 0101000020346C000000000000A8B10B41000000004A9E2441
  226883 |   675630 | 0101000020346C00000000000018B20B41000000005C9E2441
  226544 |   674911 | 0101000020346C00000000000080A70B4100000000BE982441
  226767 |   675293 | 0101000020346C00000000000078AE0B4100000000BA9B2441
  226767 |   675303 | 0101000020346C00000000000078AE0B4100000000CE9B2441


Now what I want to be able to do is to add another column or two columns with X and Y values in WGS or the standard X and Y coordinates for entry into google maps. I dont want to transform the east_north column so that I get another long string as is shown above as I cannot then integrate them into google maps. Can this be done using PostgreSQL?

Also I would like to do the opposite too. Take x and y coordinates from google maps and transform them to easting northing as above. Thanks for your help again





		
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