[GRASSLIST:5400] How to choose initial parameters?

[Ben Logan]

Hello, everyone.

I have been thinking about writing an introductory tutorial for GRASS
that would lead a total newbie to the point where I am...which isn't
all that far along, but it's a start. :-)  The tutorial would have a
very specific end (similar to the GRASS Seeds tutorial) as opposed to
being a general introduction.

Here's my problem:

Let's say I haven't created a GRASS database yet.  I have some maps
that I want to create a location for.  (The maps could be DEMs in UTM
projection or might be shapefiles in a lat/lon projection.)  Since I
don't have a database setup yet, I can't run the GRASS commands to get
information from the map data.  How do I come up with all of that
information necessary to creating a database?  Of particular interest
to me is the choice of an ellipsoid.  Back when I first set my GRASS
database up, I read somewhere that I should use the wgs84 ellipsoid.
I can't remember where I read that, and maybe it's incorrect.  How do
you know which to use, and what happens if you use the wrong one?

I'd really appreciate any help understanding this.
Ben

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Ben Logan
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