[GRASSLIST:6652] Re: Advice for a GRASS newbie
hamish_nospam at yahoo.com
Wed Apr 27 19:57:00 EDT 2005
> Hello all,
> Apologies in advance if this list is not the right place for these
> kind of questions, but I wanted to get the opinion of real-world
> GRASS users, so I figure there is no better place than here.
> I am a new GRASS user who is attempting to learn the program so I can
> use it for my master's thesis in hydrology. I purchased the second
> edition of "Open Source GIS: A GRASS GIS Approach " by M. Neteler and
> H. Mitasova, which was recommended to me as THE definitive
> GRASS-learning guide.
The book is in fact quite good. It was useful for me anyway.
> Unfortunately, the book was written for GRASS 5.3, and very early on
> in one of the tutorials, I came across a command that has become
> obsolete in GRASS 6 (the d.sites command, directed on page 30 of the
> book, which I now understand has been replaced by new functionality
> of d.vect). OK, so that's a good learning experience about how
> software changes. Then, a few pages later, I came across another
> obsolete command that was a little harder to get updated info on. At
> this point, having to figure out what commands are obsolete is
> slowing down my progress through the book. Furthermore, it seems
> like all of the GRASS 6 tutorials that are out there assume some
> familiarity with GRASS in general that I am lacking.
Ok, GRASS 5 -> GRASS 6 (aka GRASS 5.1 and 5.7) the sites and vector
functions have been radically improved. Raster and GIS functions remain
pretty much the same. As you move forward don't expect any of the sites
or vector commands to be the same. Often it is just a matter of name
(e.g. s.surf.rst -> v.surf.rst). Check the module porting list for a
Note GRASS 6 was only released 6 weeks ago. I'm sure there will be a 3rd
edition of the book at some point but writing a book doesn't happen at
the speed of Free software development... (even GRASS 6 devel :)
Now that 6 is "stable" this will change.
> So, my question is this: Which of the following strategies would the
> users on this list recommend?
> a) installing GRASS 5.3, going through the Neteler and Mitasova book,
> coming out of it knowing GRASS 5.3, then making the switch to GRASS
> 6.0 when I have some chops with 5.3
There is enough to learn without having to try and learn two versions at
once, and theoretically 6.0 is "easier" and less buggy so I would lean
towards investing your time in it. Still, if you want to go through the
tutorials in the book, by all means install 5.4 (stable version of 5.3);
it is free and you can have both versions installed on the same machine
without harm. Luckily (I think) a lot of learning GRASS is also learning
how to use UNIX and a GIS in general, both of which are not simple
things to do. So a lot of the stuff you have to painfully figure out
translates to UNIX, C programming, geospatial science etc., and will be
valuable knowledge down the road and not just sunk into some arcane
software you'll never use again. At least that goes for a lot of the
frustrating poorly documented aspects of GRASS, the assumption is
(or was) that the user was already familiar with that side of things so
the GRASS docs could gloss over them. Now that GRASS is installed on
Macs and Windows PCs that becomes much more of a barrier to learning the
software for newcomers.
> b) continuing what I am doing right now, which is going through the
> book and learning the changes as I go (and assuming that any time
> GRASS says "command not found" that it's another example of something
> that changed in the 6.0 update)
again see module porting list for an idea where to look. Just about all
of the functionality is retained. The stuff that isn't ported is usually
quite obscure in nature so no one has bothered (until someone needs it).
> c) finding an altogether different resource for learning GRASS 6.0 and
> ditch the book (this is the least desirable option, especially because
> the book was not cheap, so I would like to get some use out of it)
No, I think the book is good. Just read the sites and vector chapters
for concepts not for a recipe of exact commands.
There are several online tutorials for GRASS 6 (aka 5.7) in various
states of completion, check out the documentation section of the GRASS
website for links. But I'd do that afterwards. Depending on your needs
of course; for me raster and imagery is much more important than vectors
so the transition doesn't hit me as hard.
> Thanks in advance for any advice you may have to offer me!
hope it helps.
More information about the grass-user