[postgis-users] distance between two POINTM

[Michael Welter]

select distance_sphere(GeomFromEWKT('SRID=4269;POINTM(-105.32395 
39.50163 2563)'),GeomFromEWKT('SRID=4269;POINTM(-105.30166 39.53806 
2487)'));



Michael Fuhr wrote:
> On Sun, May 13, 2007 at 01:37:00PM -0600, Michael Welter wrote:
>> I'm trying to calculate the distance between two POINTM.  The points are 
>> as received from a Garmin GPS and include the elevation of 2500m (I'm in 
>> the mountains).
>>
>> The GPS receiver reported 5.2km between the two points, while 
>> distance_sphere() reported 4.5km.
>>
>> What is the proper method to calculate distance on the earth's surface?
> 
> Use distance_sphere() or distance_spheroid().  A common mistake is
> to define the points as (latitude longitude), which is (Y X), when
> they should be (longitude latitude), which is (X Y).  If that's not
> the problem then please post the coordinates and the query you're
> running.
> 

-- 
Michael Welter
Telecom Matters Corp.
Denver, Colorado US
+1.303.414.4980
mike at TelecomMatters.net
www.TelecomMatters.net