Newbie installation questions

[Eric G . Miller]

On Wed, Sep 06, 2000 at 01:36:03PM +1000, Gordon Keith wrote:
> I'm new to GRASS (and fairly new to GIS in general) and I'm having some
> problems getting started.
> 
> I have some bathymetry and backscatter data (ASCII lat, long, depth)
> from a swath mapper I'd like to load into a GIS as the start of doing
> some analysis on it.
> 
> I've downloaded the Grass5.0b8 binaries for linux and installed them.
> 
> When grass starts it asks me for a location, mapset and database. At
> this point I'm lost.

The 'database' is just a directory where you'll keep all of your GRASS
data.  A 'location' is a directory under the database that'll store data
for a particular 'region' (say, Tahiti!). The 'mapset' is yet another
directory under the 'location' where you might store all the data for a
particular project (say, study of Plants ...).  You'll have to create
the directory for the 'database' (I use $HOME/gis.d/), and GRASS will
create the rest as need be.  Note: 'locations' are special in that all
data in a location needs to be in the same Geographical 'region' and
have the same Projection/Coordinate system.  Every 'location' has a
mapset called PERMAMENT (a good place to store things like Coastlines or
roads or streams, things that don't change much and that you might like
to use while working with data in other mapsets).  

Anyway, there are several tutorials available from the GRASS resources
pages.  Start reading.

> Could someone tell me what these beasts are to GRASS and how I go about
> creating them. Then could you give me some pointers on how to get my
> data into GRASS.
> 
> A pointer to the appropriate documentation would be fine, I haven't
> managed to find anything that explains these basic concepts.
> 
> FWIW my data files look like this:
> 
> *** Neptune Ascii file from Kongsberg Simrad A/S ***
> Survey name: GaboReef
> Processing operator name: gjk
> Datum: WGS84
> Half axis: 6378137.0000000
> Flattening: 1/298.25722356300
> Coordinate system: Lat/Long
> Latitude min.: -37.78627580
> Longitude min.: 149.98964080
> Latitude max.: -37.69361415
> Longitude max.: 150.09606190
> Latitude cell size: 30.00 meter
> Longitude cell size: 30.00 meter
> Median depth of each cell

You have all you need there for creating a Lat/Lon location. Select
'wgs84' for the ellipsoid, the rest of this information is a direct
match to what you'll be asked.  Note: many kinds of analysis don't work
well (or at all) in a Lat/Lon system; consider projecting the data to
UTM (keep the wgs84 ellipsoid though).

See g.manual and g.help after the GRASS shell starts up...

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