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List:       postgis-users
Subject:    Re: [postgis-users] Confusing Distance
From:       "Paul Ramsey" <pramsey () cleverelephant ! ca>
Date:       2008-12-17 21:30:59
Message-ID: 30fe546d0812171330o2b83d4f6iff71be3f62bbafad () mail ! gmail ! com
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Yeah, north polar stereographic, not an optimal choice for Brazil :)

P

On Wed, Dec 17, 2008 at 12:53 PM, David William Bitner
<david.bitner@gmail.com> wrote:
> How did you chose to use 32661?  You should use an SRID that uses a
> projection that works well for the area that you are working in.
>
> On Wed, Dec 17, 2008 at 2:34 PM, sub3 <steve@subwest.com> wrote:
>>
>> Hi,
>> I was trying to calculate the distance (in NM) from two points.  I've
>> found
>> a method using distance_spheroid, but I am curious why my original method
>> didn't work correctly:
>>
>> select distance (
>>  transform( GeomFromText('Point(-76.29145663 -45.9229366415 )', 4269),
>> 32661),
>>  transform( GeomFromText('Point(-76.42922377 -45.2098919078 )', 4269),
>> 32661)
>> ) / 1852
>>
>> gives me 297 NM, but it is really a lot closer.  I thought distance()
>> would
>> return the number of meters, then I divide by the number of meters in a
>> NM.
>>
>> Thanks for any help.
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Confusing-Distance-tp21060820p21060820.html
>> Sent from the PostGIS - User mailing list archive at Nabble.com.
>>
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>
>
>
> --
> ************************************
> David William Bitner
>
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