[GRASSLIST:4331] Re: GIS visitor requests directions

Nigel McFarlane nrm at kingtide.com.au
Mon Aug 19 23:04:05 EDT 2002


ahh - I'm buried in terms again. I thought that "datum' related
to Z-elevation only. I don't understand how arguments about different
datums (data?) have any bearing on what 2D projections are
supported. I don't know what NAD27 and NAD83 are.

For world-scale maps, elevation and variations of the order of
meters (or 10s or 100s of meters) aren't an issue so even if
the datum distorts the X,Y directions, it doesn't matter for me.

My question is: can GRASS take a set of data in one
2D projection (even if its just lat-long) and project that
data into another 2D projection, regardless of which projections
the two are, and regardless of what part of the earth the data

If so, I'm doing it wrong because I can't calculate
Northing and Easting boundaries exactly to start with.

Or, as this thread seems to indicate, are projections only
supported on a case-by-case basis? (in which case, back to manifold)

thanks, Nigel

Nigel McFarlane                                  Melbourne, Australia
Software, Telecommunications, Internet, Physics  UTC +10 or +11 hours
Analysis, Programming, Writing, Education       Phone +61.3.9415.7080

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