[GRASS-user] Question about units and points of reference

[J Dougherty]

On Wednesday 23 May 2007 05:28, Wayde Allen wrote:
> On Wed, 23 May 2007, Paul Haverkamp wrote:
> > I am using 6.2.1, and g.region -p gives the info:
> >
> > projection: 1 (UTM)
> > zone:       10
> > datum:      nad83
> > ellipsoid:  grs80
> > north:      4269999
> > south:      4180119
> > west:       598614
> > east:       651978
> > nsres:      3
> > ewres:      3
> > rows:       29960
> > cols:       17788
> > cells:      532928480
>
> I've very new to all of this, so please forgive what may be a very obvious
> question, but can someone explain the units for these coordinates?  I'm
> thinking that "north: 4269999" must indicate the distance North of some
> reference location, perhaps the equator?  It this in feet, meters, miles,
> kilometers, or something else entirely?
>
> - Wayde
>
The UniversalTransverse Mecator (UTM) divides the globe up into 60 "Zones."  
Zone 10 takes in the western coast of North America and for those of us who 
live and work here, and use UTM coordinates, we recognize a rectangle that 
takes in the north-central portion of the Great Valley of California between 
about Woodland on the north and Manteca on the south, effectively the 
Sacramento - San Joaquin river delta and the valley area surrounding it on 
the north, east, and west.  It's a pretty big region.

JDougherty