from two tables make a new one

Question

I have two tables both of them has linestring geometry. I try to make a new one which contain the first one and from the second take only the decimal v when the linestring of the first table touch a linestring of the second.

CREATE TABLE Three AS(
SELECT st_astext(r.geom),e."v" FROM r , e WHERE ST_Touches(e.geom, ST_Transform(r.geom,4326)));

But i am not take an error or a result , the geom of r is in another srid than the 4326 which is the e and i transform it.

Answer 1

Not sure what the problem is, but just to check further, you might try some checks like:

SELECT ST_SRID(geom) FROM r; 
SELECT ST_SRID(geom) FROM e; 
SELECT ST_Touches(e.geom , ST_Transform(r.geom, 4326)) FROM e,r;  

Also note that ST_Touches() returns true only if lines cross exactly at a vertex or node. For example:

SELECT ST_Touches('LINESTRING(0 0, 2 2)'::geometry, 'LINESTRING(0 2, 2 0)'::geometry);

returns false. You might be wanting ST_Crosses(), or ST_Intersects().