Re: [Geotools-gt2-users] What are the distance units used by DWithin
David R Robison ha scritto: > OK. I am using this filter as part of a geoserver wfs call. Is there a > way to tell the query to reproject the coordinates into something that > has a better unit, such as meters? Thanks, David Robison Nope... the filter will go straight to postgis, sorry... Cheers Andrea - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
Re: [Geotools-gt2-users] What are the distance units used by DWithin
OK. I am using this filter as part of a geoserver wfs call. Is there a way to tell the query to reproject the coordinates into something that has a better unit, such as meters? Thanks, David Robison Andrea Aime wrote: > David Robison ha scritto: >> Forgive my ignorance, I am using a filter such as: >> >> >> the_geom >> >> -77.46074,37.76504 >> >> .001 >> >> >> How do I know what units the distance is in? How would I go about >> specifying a projection (if I need one)? Is there a default >> projection that is used? The data is in a PostGIS database, is the >> information on the projection available in the database? Any help >> would be appreciated. > > Unit can be expressed but will be completely disregarded, dwithin > will be translated into a postgis query verbatim using the > ST_DWithin function > (http://postgis.refractions.net/docs/ch06.html#id2630911) > which again is unit agnostic. > > Long story short, there is no way to have coordinates expressed > in one unit and have the filter use another. Everything works fine > if and only if the distance is expressed in the same units as > the coordinates (which does not make much sense when you're playing > with geographic coordinates). > > Cheers > Andrea -- David R Robison Open Roads Consulting, Inc. 708 S. Battlefield Blvd., Chesapeake, VA 23322 phone: (757) 546-3401 e-mail: [EMAIL PROTECTED] web: http://openroadsconsulting.com blog: http://therobe.blogspot.com book: http://www.xulonpress.com/book_detail.php?id=2579 - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
Re: [Geotools-gt2-users] What are the distance units used by DWithin
David Robison ha scritto: > Forgive my ignorance, I am using a filter such as: > > > the_geom > > -77.46074,37.76504 > .001 > > > How do I know what units the distance is in? How would I go about > specifying a projection (if I need one)? Is there a default projection > that is used? The data is in a PostGIS database, is the information on > the projection available in the database? Any help would be appreciated. Unit can be expressed but will be completely disregarded, dwithin will be translated into a postgis query verbatim using the ST_DWithin function (http://postgis.refractions.net/docs/ch06.html#id2630911) which again is unit agnostic. Long story short, there is no way to have coordinates expressed in one unit and have the filter use another. Everything works fine if and only if the distance is expressed in the same units as the coordinates (which does not make much sense when you're playing with geographic coordinates). Cheers Andrea - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
Re: [Geotools-gt2-users] What are the distance units used by DWithin
Forgive my ignorance, I am using a filter such as: the_geom -77.46074,37.76504 .001 How do I know what units the distance is in? How would I go about specifying a projection (if I need one)? Is there a default projection that is used? The data is in a PostGIS database, is the information on the projection available in the database? Any help would be appreciated. Thanks, David _ From: Andrea Aime [mailto:[EMAIL PROTECTED] To: David Robison [mailto:[EMAIL PROTECTED] Cc: geotools-gt2-users@lists.sourceforge.net Sent: Mon, 05 Nov 2007 15:45:28 -0500 Subject: Re: [Geotools-gt2-users] What are the distance units used by DWithin David Robison ha scritto: > I am trying to use DWithin for a filter. However, I don't know what > distance units it will use by default. Is there a way to tell? The data > is in EPSG:4326 DWithin works with euclidean distance, so you won't be able to use it in EPSG:4326. You can use it only in projected CRS where a flat world assumption can work. Cheers Andrea - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
Re: [Geotools-gt2-users] What are the distance units used by DWithin
David Robison ha scritto: > I am trying to use DWithin for a filter. However, I don't know what > distance units it will use by default. Is there a way to tell? The data > is in EPSG:4326 DWithin works with euclidean distance, so you won't be able to use it in EPSG:4326. You can use it only in projected CRS where a flat world assumption can work. Cheers Andrea - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ ___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
[Geotools-gt2-users] What are the distance units used by DWithin
I am trying to use DWithin for a filter. However, I don't know what distance units it will use by default. Is there a way to tell? The data is in EPSG:4326 Thanks, David Robison- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/___ Geotools-gt2-users mailing list Geotools-gt2-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
