GEOMETRIES with different SRIDs

[africa4you]

Hi

I have two points in different SRID's and would like to calculate the distance between them, unfortunately this type of operation doesnt seem to be valid (Operation on two GEOMETRIES with different SRIDs ). Any help in solving this issue would be appreciated. Please see the sql below:

Kind regards

Grant Edwards

SELECT postgis_full_version()
"POSTGIS="1.3.3" GEOS="3.0.0-CAPI-1.4.1" PROJ="Rel. 4.6.0, 21 Dec 2007" USE_STATS"



SELECT utmzone(ST_Centroid(setsrid((makepoint(28.060455, -26.056947)),4326))); //Johannesburg (utmzone = 32735)
EPSG Projection 32735 - WGS 84 / UTM zone 35S
http://spatialreference.org/ref/epsg/32735/

SELECT utmzone(ST_Centroid(setsrid((makepoint(18.3793284, -33.9228922)),4326))); //Cape Town (utmzone = 32734)
EPSG Projection 32734 - WGS 84 / UTM zone 34S
http://spatialreference.org/ref/epsg/32734/

SELECT  ST_Distance(ST_Transform(setsrid((makepoint(28.060455, -26.056947)),4326),utmzone(ST_Centroid(setsrid((makepoint(28.060455, -26.056947)),4326)))) ,
                    ST_Transform(setsrid((makepoint(18.3793284, -33.9228922)),4326),utmzone(ST_Centroid(setsrid((makepoint(18.3793284, -33.9228922)),4326)))))  as dist_meters


ERROR:  Operation on two GEOMETRIES with different SRIDs

[Paul Ramsey-3]

Just skip the projections altogether.

select st_distance_sphere(st_makepoint(28.060455,
-26.056947),st_makepoint(18.3793284, -33.9228922))

This falls apart for queries with large tables, etc, because there's
no _sphere equivalent of st_dwithin that can leverage an index well.

P.

On Sun, Jun 14, 2009 at 9:20 AM, africa4you<a4uofbiz@...> wrote:

>
> Hi
>
> I have two points in different SRID's and would like to calculate the
> distance between them, unfortunately this type of operation doesnt seem to
> be valid (Operation on two GEOMETRIES with different SRIDs ). Any help in
> solving this issue would be appreciated. Please see the sql below:
>
> Kind regards
>
> Grant Edwards
>
> SELECT postgis_full_version()
> "POSTGIS="1.3.3" GEOS="3.0.0-CAPI-1.4.1" PROJ="Rel. 4.6.0, 21 Dec 2007"
> USE_STATS"
>
>
>
> SELECT utmzone(ST_Centroid(setsrid((makepoint(28.060455,
> -26.056947)),4326))); //Johannesburg (utmzone = 32735)
> EPSG Projection 32735 - WGS 84 / UTM zone 35S
> http://spatialreference.org/ref/epsg/32735/
>
> SELECT utmzone(ST_Centroid(setsrid((makepoint(18.3793284,
> -33.9228922)),4326))); //Cape Town (utmzone = 32734)
> EPSG Projection 32734 - WGS 84 / UTM zone 34S
> http://spatialreference.org/ref/epsg/32734/
>
> SELECT  ST_Distance(ST_Transform(setsrid((makepoint(28.060455,
> -26.056947)),4326),utmzone(ST_Centroid(setsrid((makepoint(28.060455,
> -26.056947)),4326)))) ,
>                    ST_Transform(setsrid((makepoint(18.3793284,
> -33.9228922)),4326),utmzone(ST_Centroid(setsrid((makepoint(18.3793284,
> -33.9228922)),4326)))))  as dist_meters
>
>
> ERROR:  Operation on two GEOMETRIES with different SRIDs
> --
> View this message in context: http://www.nabble.com/GEOMETRIES-with-different-SRIDs-tp24022339p24022339.html
> Sent from the PostGIS - User mailing list archive at Nabble.com.
>
> _______________________________________________
> postgis-users mailing list
> postgis-users@...
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>

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[africa4you]

Some parts of this message have been removed. Learn more about Nabble's security policy.

Thank you Paul, this is most useful

---

From: Paul Ramsey <pramsey@...>
To: PostGIS Users Discussion <postgis-users@...>
Sent: Sunday, June 14, 2009 8:49:36 PM
Subject: Re: [postgis-users] GEOMETRIES with different SRIDs

Just skip the projections altogether.

select st_distance_sphere(st_makepoint(28.060455,
-26.056947),st_makepoint(18.3793284, -33.9228922))

This falls apart for queries with large tables, etc, because there's
no _sphere equivalent of st_dwithin that can leverage an index well.

P.

On Sun, Jun 14, 2009 at 9:20 AM, africa4you<a4uofbiz@...> wrote:

>
> Hi
>
> I have two points in different SRID's and would like to calculate the
> distance between them, unfortunately this type of operation doesnt seem to
> be valid (Operation on two GEOMETRIES with different SRIDs ). Any help in
> solving this issue would be appreciated. Please see the sql below:
>
> Kind regards
>
> Grant Edwards
>
> SELECT postgis_full_version()
> "POSTGIS="1.3.3" GEOS="3.0.0-CAPI-1.4.1" PROJ="Rel. 4.6.0, 21 Dec 2007"
> USE_STATS"
>
>
>
> SELECT utmzone(ST_Centroid(setsrid((makepoint(28.060455,
> -26.056947)),4326))); //Johannesburg (utmzone = 32735)
> EPSG Projection 32735 - WGS 84 / UTM zone 35S

> http://spatialreference.org/ref/epsg/32735/
>
> SELECT utmzone(ST_Centroid(setsrid((makepoint(18.3793284,
> -33.9228922)),4326))); //Cape Town (utmzone = 32734)
> EPSG Projection 32734 - WGS 84 / UTM zone 34S
> http://spatialreference.org/ref/epsg/32734/

>
> SELECT  ST_Distance(ST_Transform(setsrid((makepoint(28.060455,
> -26.056947)),4326),utmzone(ST_Centroid(setsrid((makepoint(28.060455,
> -26.056947)),4326)))) ,
>                    ST_Transform(setsrid((makepoint(18.3793284,
> -33.9228922)),4326),utmzone(ST_Centroid(setsrid((makepoint(18.3793284,
> -33.9228922)),4326)))))  as dist_meters
>
>
> ERROR:  Operation on two GEOMETRIES with different SRIDs
> --

> View this message in context: http://www.nabble.com/GEOMETRIES-with-different-SRIDs-tp24022339p24022339.html
> Sent from the PostGIS - User mailing list archive at Nabble.com.
>
> _______________________________________________
> postgis-users mailing list
> postgis-users@...
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>
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