Hi Jody, Thanks for the response.
I am having difficulty adding my own SRID, and getting uDig to recognize it. What I really want is to be able to support this in my own custom application, but for now, I am running uDig from Eclipse -- I don't know if that changes things. This is what I've done: I created a geometry table in PostGIS, and set the SRID to 3395 (the SRID in PostGIS for "WGS 84 / World Mercator"). When I load the layer into uDig, the CRS is set to 4326. That didn't work. Next, I created a geometry table in PostGIS, and set the SRID to 41001 (the SRID in uDig for "WGS84 / Simple Mercator" -- this is nearly the same, and would suit my purposes if it would work). When I load the layer into uDig, the CRS is set to 4326. I assumed that the problem was that PostGIS and uDig had to have the same CRS in both their systems, so the SRID in the PostGIS spatial_ref_sys table matches the EPSG code in uDig's Coordinate System dialog. Sure enough, if I set the PostGIS spatial reference to something else (for my test, I used EPSG:4269), then when it loads into uDig, the CRS is set correctly. Additionally, when I attempt to add the definition from PostGIS (the srtext from the spatial_ref_sys table) for 3395 into the Custom CRS box in uDig, I can press "Apply" and "OK" to my heart's content, but the dialog never closes, and I can't get out of the dialog without canceling. Please advise, David On Wed, Feb 11, 2009 at 6:42 PM, Jody Garnett <[email protected]>wrote: > Mark Leslie is the postgis guy I know these days and he can confirm or deny > what I say here :-) > > You can add your own SRID codes to to PostGIS and define one th be generic > cartesian 2D if you like. UDig will pick up this WKT definition and be > fairly happy. > > In uDig you click to change the projection; there are two tabs (one where > you select the formal epsg definition from a list; and a second where you > can type in your own WKT). You can also right lick on a layer and "force" a > change of projection (if the data source is wrong for example - it does > happen). > > Mercator is supported in our referencing library so you should be able to > proceed resonably well. Normally PostGIS SRID codes line up with the EPSG > codes ... > > Jody > > David Zwarg wrote: > >> Hello, >> >> I am wondering if there is a way to use the World Mercator projection in >> PostGIS in uDig. I am unable to use either the PostGIS (3395) or the uDig >> (41001) EPSG codes for world mercator in my PostGIS layer -- they both show >> up as Generic cartesian 2D. As soon as I attempt to add geometry and edit >> geometry, uDig goes into an endless loop of IllegalArgumentExceptions. >> >> However, if I use an EPSG code that appears in BOTH postgis and uDig, it >> seems to work alright. If there was a way to represent Generic cartesian >> coordinates in PostGIS, that would be preferable, but -1 causes this same >> IllegalArgumentException spiral. Am I missing a general projection that >> would be more suitable? >> >> Also, during this experiment, I was unable to create a custom CRS in the >> uDig map preferences, or by clicking on the button in the status bar. How >> do you create a custom CRS from a known WKT? >> >> Thanks, >> David >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> User-friendly Desktop Internet GIS (uDig) >> http://udig.refractions.net >> http://lists.refractions.net/mailman/listinfo/udig-devel >> >> > > _______________________________________________ > User-friendly Desktop Internet GIS (uDig) > http://udig.refractions.net > http://lists.refractions.net/mailman/listinfo/udig-devel >
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