|
From: Richard G. <ric...@gm...> - 2008-07-02 02:04:06
|
The false easting (x_0) must always be in meters, even for coordinate systems that are in feet. On Tue, Jul 1, 2008 at 3:03 PM, David Zwarg <dz...@av...> wrote: > Hello, > > I am using proj4js, and I am having difficulty getting good projection with > a new projection definition. It is entirely possible that I don't have the > correct syntax for the definition file (or that I am totally missing > something required), but it's giving results that are off by a factor of 3 > in 1 dimension (either X or Y, but not both). > > I am creating a definition for Pennsylvania State Plane, and this is the > file EPSG2272.js: > > Proj4js.defs["EPSG:2272"] = "+proj=lcc \ > +lon_0=-77.75 \ > +lat_0=39.33333333333334 \ > +lat_1=39.9333333333333 \ > +lat_2=40.96666666666667 \ > +y_0=0.0 \ > +x_0=1968500.00 \ > +ellps=GRS80 \ > +datum=NAD83 \ > +nadgrids=@null +no_defs"; > > I searched in http://www.epsg-registry.org/, and those are correct decimal > degrees values. I try to transform the location of Philadelphia, PA ( > -75.163808,39.951639 ), and I always get x:2189468, y:71889. I am expecting > something like x:2694800,y:236500. > > At first, I thought it was a ft/meter conversion, but when I add > "+to_meter=0.3048006096012192" to the definition, the projected Y coordinate > looks good, but the X coordinate is way off. > > Any help would be greatly appreciated, > Thanks, > David > > ------------------------------------------------------------------------- > Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ > Mapbuilder-proj mailing list > Map...@li... > https://lists.sourceforge.net/lists/listinfo/mapbuilder-proj > > -- Richard Greenwood ric...@gm... www.greenwoodmap.com |