How to check if a geometry of type Point is inside another geometry of type MultiPolygonZM using Postgis functions?

Question

I want to know if there's a way to check if a geometry of type Point is inside a geometry of type MultiPolygonZM, ignoring the Z coordinate, I just want to know if my Point(lat, lng) is inside a MultiPolygonZM.

This is an example of a MultiPolygonZM geometry in my database; I used ST_AsText to get a text representation of the geom :

"MULTIPOLYGON ZM (((
570277.5312 3592073.8077 460.900200000004 -1.79769313486232e+308,
570262.0283 3592073.7806 460.712700000004 -1.79769313486232e+308,
570262.4922 3592086.4664 460.705199999997 -1.79769313486232e+308,
570278.0406 3592086.5792 460.697700000004  (...)"

I tried ST_CONTAINS, ST_INTERSECTS like this :

SELECT * FROM CITIES
WHERE
ST_Intersects(ST_SetSRID(geom, 4326), ST_SetSRID(ST_MakePoint(3.67622580, 32.48549230), 4326))

SELECT * FROM CITIES
WHERE
ST_Contains(ST_SetSRID(geom, 4326), ST_SetSRID(ST_MakePoint(3.67622580, 32.48549230), 4326)).

My table uses 4326 as SRID, but i wanted to set it using ST_SetSRID to be sure that all the geoms have the same SRID

But it doesn't work! All the results are false!

Any solution ?

Answer 1

Either ST_Contains or ST_Intersects should work. You can use ST_Force_2D to make a polygon be 2D only.

However, this does not affect the results of an intersect. Note that both of the following, which only differ in a ST_Force2D function, return true (t):

SELECT  
    ST_Intersects(
          ST_Force2d(
               ST_GeomFromText('POLYGON((0 0 2,0 5 2,5 0 2,0 0 2))')),
               ST_MakePoint(2,2));

SELECT  
     ST_Intersects(
            ST_GeomFromText('POLYGON((0 0 2,0 5 2,5 0 2,0 0 2))'),
            ST_MakePoint(2,2));

So, it is possible that your problem lies elsewhere. If you could provide an example of one of your PolygonZM that you think should intersect a point, it would be easier to investigate.

Also, it is generally not a good idea to use ST_SetSRID in queries, but to update the columns using UpdateGeometrySRID. This will have the additional benefit of updating the geometry_columns meta data table, making errors involving different SRIDs impossible and generally keeping your db cleaner and your queries shorter. If you need to use a different SRID, you can always use ST_Transform.

One form, if you exclude the schema name, would be:

SELECT updategeometrysrid('cities', 'geom', 4326);