# [postgis-users] ST_Distance issue

Archana Sachin Ghag Archana_Ghag at infosys.com
Thu Nov 17 19:46:40 PST 2011

```I am calculating distance from my current location with all available regions(polygons) in my table.
I am using ST_Distance method for this.
My regions are stored with SRID = 900913.

Distance for point in Europe from USA region is coming as 122.78.
How come this possible. These regions are so far.

Here is my query. Can you please suggest me how can I get actual distance in meters here.

SELECT ST_distance
(st_geomfromtext('point(-123.574219125 47.8131546948944 0)', 900913),
st_geomfromtext('LINESTRING(-0.791015625 48.4874864798841,9.4921875 54.5975278521139,27.59765625 55.3541353102106,36.38671875 48.3124279040718,22.32421875 40.3465441211801,5.888671875 43.8662180065564,-0.791015625 48.4874864798841)', 900913)
)

Query returns 122.785055218779

SELECT ST_Distance_Sphere
(st_geomfromtext('point(-123.574219125 47.8131546948944 0)', 900913),
st_geomfromtext('LINESTRING(-0.791015625 48.4874864798841,9.4921875 54.5975278521139,27.59765625 55.3541353102106,36.38671875 48.3124279040718,22.32421875 40.3465441211801,5.888671875 43.8662180065564,-0.791015625 48.4874864798841)', 900913)
)

Query returns 7808837.70565995

But still its less only as this in in meters. Is it bcs I m calculating distance between point and polygon.
ST_Distance_Sphere works great for point to point distance.
What is significance of SRID here. Am I missing something?
Which SRID should we use for general purpose.

Thanks,
Archana Ghag
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