[GRASS-user] Manually Defining Location

Rich Shepard rshepard at appl-ecosys.com
Fri May 20 17:39:22 EDT 2011


   I have tried several times to use the location wizard without success.

   These files were exported from ArcGIS as shapefiles and they seem to have
different projections from what the location wizard expects. Perhaps I need
custom proj4 strings to create the locations. Following is the contents of a
representative .prj file:

GEOGCS["GCS_North_American_1927",
DATUM["D_North_American_1927",
SPHEROID["Clarke_1866",6378206.4,294.9786982]],
PRIMEM["Greenwich",0.0],
UNIT["Degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",500000.0],
PARAMETER["False_Northing",-2000000.0],
PARAMETER["Central_Meridian",-115.583333],
PARAMETER["Scale_Factor",0.9999],
PARAMETER["Latitude_Of_Origin",34.75],
UNIT["Foot_US",0.3048006096012192]]

   Notice there are two units in this guy: degrees and US Feet.

   When I specify Transverse Mercator (tmerc) and NAD27 the creation attempt
fails because it expects units to be meters and sees US feet.

   What should I do to create a location for these maps?

Rich


More information about the grass-user mailing list