[postgis-users] difference between contains and within

[Chander Ganesan]

Dave Potts wrote:
> I trying to work out the number of points that spaitially inside a 
> polygon, looking at the manual there are two functions that seem to do 
> the right thing, contains and within.
>
> Q. Whats the difference between the two functions?
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I believe they are the same, just with the arguments swapped. 

st_within(A, B) would return 1 if A is completely within B.
st_contains(A,B) would return 1 if B was completely within A

thanks

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Chander Ganesan
Open Technology Group, Inc.
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