Quinn Hart wrote:
Can someone explain how g.setproj works. According to the man page, it
should prompt for the projection. In practice howver, it seems to read
the proj from DEFAULT_WIND. The problem I'm finding is that the only
valid proj: values are:
0:(xy)
1:(utm)
2:(state plane)
3:(ll)
and g.setproj doesn't like anything else. So how do I get nifty
projections like aea,lcc,merc,tmerc? Note this is the same list that
comes up for me when making a new location. Shouldn't that include all these
projections?Thanks in advance.
Quinn Hart (qjhart@ucdavis.edu)
Dept. Land, Air, and Water Resources
UC Davis
Hello Quinn
You do not need g.setproj to create a new location in a projection other than
the GRASS defaults.
Actually, if you create a new location and the files PROJ_INFO and PROJ_UNITS
directly you can use all the projections supported by the software PROJ and
MAPGEN!! I think that more than 60 different projections are currently
available. The advantage is that although all GRASS modules do not recognize
these projections, v.proj does, so you can easily import/export vector data.
I have been using the Lambert Azimuthal Equal Area proj for the last two years,
and never enountered any major problems.
About the aea,lcc,merc,tmerc projections, GRASS accepts them when you create
a new location while getting into GRASS. I have never tried g.setproj since
PROJ_INFO and PROJ_UNITS must be created by hand for non-standard projs.
You should also check which version of GRASS you are using since version 4.1
deals with projection in a different manner than 4.0.
Do not hesitate to contact me, if you need more help.
--
Anne Gisiger FAX: (501) 575-3846
CAST, Center for Advanced Spatial Technologies TEL: (501) 575-6159
12 Ozark Hall, University of Arkansas
Fayetteville AR 72701 anne@cast.uark.edu