[postgis-users] distance query is not returning expected result

Jimmy Forrester jimmy at sparkleinteractive.co.uk
Sun Jan 25 07:03:58 PST 2009


Hey all, I'm new to postgis and implementing a few geographic features in to
my site. I'm having a bit of difficulty getting my distance calculations
working:

select ST_Distance(    ST_Transform(ST_SetSRID(ST_Point(53.7996374,
-1.54911),     4326), 2163),
            ST_Transform(ST_SetSRID(ST_Point(53.6451179, -1.784876),
4326), 2163)
        ) / 1000


In the query above I'm testing the distance between Leeds & Huddersfield.
I'm trying to convert the 4326 srid geom to  srid 2163 which is meters (i
think!). For an unknown reason this is returning 64 km which i know is
incorrect.

I've plotted the coords on google maps and they are definitely correct,
google maps says the distance is about 24 km. see:

http://www.google.com/maps?f=d&source=s_d&saddr=53.7996374,+-1.54911&daddr=53.6451179,+-1.784876&hl=en&geocode=FdXqNAMdylzo_w%3BFT6PMgMd1MPk_w&mra=ls&dirflg=w&doflg=ptk&sll=53.722107,-1.645889&sspn=0.161297,0.418854&ie=UTF8&ll=53.72231,-1.667175&spn=0.161296,0.418854&t=h&z=12

Any help on this would be great,

Thanks,
Jimmy
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