[osgeo4w-dev] [osgeo4w] #320: Transformation Problem with Merchich Sahara Projections

OSGeo4W trac_osgeo4w at osgeo.org
Wed Dec 5 08:26:51 PST 2012

#320: Transformation Problem with Merchich Sahara Projections
Reporter:  ysid    |        Owner:  osgeo4w-dev@…              
    Type:  defect  |       Status:  closed                     
Priority:  major   |    Component:  Package                    
 Version:          |   Resolution:  fixed                      
Keywords:          |  
Changes (by jlacroix):

  * status:  new => closed
  * resolution:  => fixed


 This problem comes from a default PROJ4 setting. By default, PROJ4 tries
 to define the +lat_1 and +lat_2 parameters to work with a U.S. map for all
 lcc and aea based projection. This is defined in

 When not using the environment variables, cs2cs simply didn't find this
 default configuration file and the good result was produced.

 To prevent the use of this default configuration file, PROJ4 has the
 +no_defs parameters. If you use this parameter, like it is in the epsg
 file and the cs2cs website, you should get the good result.

 > cs2cs.exe -f "%.03f%" +proj=longlat +datum=WGS84 +pm=greenwich
 +ellps=WGS84 +to +proj=lcc +units=m +towgs84=31,146,47,0,0,0,0
 +pm=greenwich +a=6378249.2 +rf=293.466021293627 +lon_0=-5.4 +x_0=1500000
 +y_0=400000 +lat_0=22.5 +lat_1=22.5 +k_0=0.999616437 +no_defs
 310159.282      20443.066 -80.008[[BR]]

Ticket URL: <http://trac.osgeo.org/osgeo4w/ticket/320#comment:1>
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