[GRASS-user] Projection information

[Hamish]

stephen sefick wrote:
> These are three different projection
> locations that I have set up over
> the past year with ever changing GRASSes.  tcl/tk
> interface up to the
> new GRASS6.4.1svn.  I have consistently kept
> everything in the correct
> projections for input data.
> 
> ftbn: utm nad83 grs80 zone 17
> srs: utm nad83 grs80 zone 17
> ftbn: utm nad83 grs80 zone 17
> 
> 
> should I be worried that the ProjInfo files for the three
> below differ slightly?  Can I safely make them all look the
> same?  Does this matter?  Thanks in advance for all of the help.
> 
> 
> ftbr:
> name: Universal Transverse Mercator
> datum: nad83
> towgs84: 0.000,0.000,0.000
> proj: utm
> ellps: grs80
> a: 6378137.0000000000
> es: 0.0066943800
> f: 298.2572221010

a, es, and f are just grs80 expanded, try `proj -le` from the command line.
+towgs84=0,0,0 pretty much means "don't do anything to get to wgs84"

I see that proj=utm but the zone= is missing. If so, the projection
definition is incomplete.


> srs:
> name: Universal Transverse Mercator
> proj: utm
> datum: nad83
> ellps: grs80
> zone: 17
> no_defs: defined

equivalent, see http://trac.osgeo.org/proj/wiki/GenParms for details.

> ftbn:
> name: UTM
> datum: nad83
> towgs84: 0.000,0.000,0.000
> proj: utm
> ellps: grs80
> a: 6378137.0000000000
> es: 0.0066943800
> f: 298.2572221010
> zone: 16

note the above says zone 16, not 17. otherwise equivalent.


Hamish