[GRASSLIST:1963] Re: [GRASS5] [bug #755] (grass) help (again)

Rich Shepard rshepard at appl-ecosys.com
Fri Jun 15 18:17:46 EDT 2001


On Fri, 15 Jun 2001, Request Tracker wrote:

> this bug's URL: http://intevation.de/rt/webrt?serial_num=755
> -------------------------------------------------------------------------

Rafael,

  This should have been sent to the grass mail list (grasslist at baylor.edu)
rather than the grass5-development mail list.

>   Thank you for the fast answer.  I am a biologist working in a
> biodiversity survey in Brazil. At this moment I am evaluating the
> possibility of using a GIS software to analyse our data (insects and their
> host plants distributed in a macrogeographic scale). As I am a first time
> GRASS GIS user, I would like to know if there is any kind of "step-by-step
> tutorial" available.

  The only tutorial uses the 'spearfish' data base, and it's intended to
teach the mechanics of using GRASS, not spatial analyses.

>  Do you think I would have advantages using GRASS GIS or you recommend a
> simpler software (as ArcView)?

  Well, GRASS costs nothing, AV will cost several thousand US$. Is it
simpler? Yes. But, that simplicity comes at the cost of limited abilities,
especially for the type of work I believe you want to do.

  I'm not going to address the problems of getting GRASS running on your
system; I'll let others handle that. What I will offer is this: the
variables of $GISBASE, Location and mapset are directories, in that order.
So, for example, we have /mnt/usr4/projects/nevada/gf for one project on
which we are working. Here, projects/ == $GISBASE, nevada/ == location and
gf/ == mapset. Create a new directory tree for your project and when you
invoke GRASS it will ask for the location and mapset. If it doesn't exist,
GRASS will create it.

  What I would recommend you do while you're waiting to get GRASS running
properly is sit down and decide _exactly_ what questions you want to ask.
Then look at the modules to see which ones will produce answers to those
questions. After this, determine what data you need to collect to feed into
the modules. To be candid, you need to do this regardless of the software
you use.

  In a prior life as a statistical consultant, I had grad students and
"researchers" come to me with a year or two worth of data and ask me to
analyze it for them. Not once were the data collected in a form that would
allow valid analyses addressing the questions they were supposed to answer.

HTH,

Rich

Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
            2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
 + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com
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