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I have this query that returns the_geom as text. However how could I also apply a transform to the same query. I can do this separately with the second example. Though I would like to do this to all the rows in my table, and in that example I copied the st_astext output into the transform query.

select sitename, st_astext(the_geom) from sites_tbl;

sitename | st_astext

Belfast A | POINT(145592 530021)

ST_AsText(ST_Transform(ST_SetSRID('POINT(145592 530021)'::geometry,27700), 4326));

4

You can use ST_Transform in your first query too.

select sitename, st_astext( ST_Transform( the_geom, 4326 ) ) from sites_tbl;
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This is a query I use to write out the LAT/LON of points from data stored in State Plane (feet):

select 
residential_block_points.geoid_num
, st_x(st_centroid(st_transform(residential_block_points.geom, 4326))) as X
, st_y(st_centroid(st_transform(residential_block_points.geom, 4326))) as Y
from 
residential_block_points

and you could add this data as new fields in the existing table:

ALTER TABLE "residential_block_points" ADD x double precision;
ALTER TABLE "residential_block_points" ADD y double precision;
UPDATE "residential_block_points" SET x = st_x(st_centroid(st_transform(residential_block_points.geom, 4326)));
UPDATE "residential_block_points" SET y = st_y(st_centroid(st_transform(residential_block_points.geom, 4326)));

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