Le vendredi 29 janvier 2016 16:24:00, Daniel Fenton a écrit : > Even, > > I'm not sure if this helps,
Me neither ;-), but thanks for jumping into this. > but in dealing with an issue with WKID 5514, EPSG:5514 is east-north oriented (like EPSG:5221, the GIS friendly equivalent of EPSG:2065), so it is naturally dealt with by proj.4. > this WKT workers to properly convert data from WGS84. This was confirmed > against a customer's source data. Hum seing stuff like PARAMETER["X_Scale",-1],PARAMETER["Y_Scale",1],PARAMETER["XY_Plane_Rotation",90] I'm not sure which projection engine is used behind. Such parameters aren't needed with proj.4 since AFAIU it naturally expects easting,northing coordinates to be provided as input for the +proj=krovak method (this must be the implementation of the "Krovak (North Oriented)" / EPSG:1041 method rather than original Krovak south/west oriented) (funnly looking at the source of a PJ_krovak.c, I see there's a "+czech" parameter that can be provided to reverse the signs of x/y . hum....) > ' > PROJCS["S-JTSK_Krovak_East_North",GEOGCS["GCS_S_JTSK",DATUM["Jednotne_Trigo > nometricke_Site_Katastralni",SPHEROID["Bessel_1841",6377397.155,299.1528128 > ]],TOWGS84[589,76,480,0,0,0,0],PRIMEM["Greenwich",0],UNIT["Degree",0.017453 > 292519943295]],PROJECTION["Krovak"],PARAMETER["False_Easting",0],PARAMETER[ > "False_Northing",0],PARAMETER["Pseudo_Standard_Parallel_1",78.5],PARAMETER[ > "Scale_Factor",0.9999],PARAMETER["Azimuth",30.28813975277778],PARAMETER["Lo > ngitude_Of_Center",24.83333333333333],PARAMETER["Latitude_Of_Center",49.5], > PARAMETER["X_Scale",-1],PARAMETER["Y_Scale",1],PARAMETER["XY_Plane_Rotation > ",90],UNIT["Meter",1],AUTHORITY["EPSG","102067"]] ' > > Daniel > > *Daniel Fenton* > *Software Engineer | Esri R&D* > *https://koopjs.github.io <https://koopjs.github.io>* > On Thu, Jan 28, 2016 at 12:05 PM Even Rouault <even.roua...@spatialys.com> > > wrote: > > Hi, > > > > I'm having a look at the following all related issues : > > https://trac.osgeo.org/postgis/ticket/1940 > > https://trac.osgeo.org/proj/ticket/185 > > https://trac.osgeo.org/gdal/ticket/4762 > > > > related to EPSG:2065 support, ie "S-JTSK (Ferro) / Krovak". There's an > > issue > > about the datum shift used, but that's an easy one compared to a more > > serious > > one regarding axis order. > > > > The proj.4 krovak method expects the first value of a coordinate pair to > > be a > > easting, and the second value a northing. Whereas original Krovak > > (EPSG:2065) > > is supposed to be southing first, westing second. > > > > https://trac.osgeo.org/gdal/ticket/4762 suggests to add a "+to_meter=-1" > > parameter. Which means that the coordinates supplied are first westing, > > second > > southing (instead of "+to_meter=-1", a cleaner equivalent way is to use > > "+axis=wsu", meaning westing,southing,up ) > > But EPSG would mandate southing,westing. > > > > But admitedly, for less exotic coordinate systems with official EPSG axis > > order > > latitude,longitude (EPSG:4326...) or northing,easting (some Finland > > projected > > CRS for example) we have never introduced in GDAL WKT or proj.4 strings > > the +axis option, and the application/user does the coordinate switch > > itself before passing that to GDAL/proj. > > > > So, does that sound OK that a user providing coordinates advertized to be > > in > > EPSG:2065 does that in westing, southing order ? Or was this something > > particular to this user ? (I'd note that the dataset mentionned in the > > ticket > > is a GML resulting from a WFS server, and we all know the axis ordering > > issues > > related to WFS) > > > > What a mess... > > (Using EPSG:5221 which is the easting, northing variant avoids those > > headaches) > > > > Even > > > > -- > > Spatialys - Geospatial professional services > > http://www.spatialys.com > > _______________________________________________ > > gdal-dev mailing list > > gdal-dev@lists.osgeo.org > > http://lists.osgeo.org/mailman/listinfo/gdal-dev -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
