[GRASSLIST:7429] Re: silly question?

[Hamish]

> I've been an <GASP>  E$RI arc/info workstation user for 10+ years, and
> i'm finally (successfully) jumping ship.  from what i read, i see,
> GRASS can do everything workstation can, not to mention its
> plug-ability with Quantum GIS and other open source software.
> 
> Does anyone know if there has ever been a document created that is
> somewhat of a HOWTO in a GRASS approach from a workstation mindset? 
..
> In other words, is there some document that illustrates tasks
> performed in workstation with corrisponding commands document of how
> to do the same procedures in GRASS?  


I remember someone talking about putting such a document together maybe 6
months ago; you'd have to search the mailing list archive for it.

I seem to recall the discussion went something like "please document
your progress and post your findings to the Wiki so that others might
benefit from your journey." I don't know if that ever happened, but you
might take up the same task. It is very hard for those without a ESRI
background to know what the preconceived ways of doing things are. ie it
needs to be done by someone in your shoes.

http://grass.gdf-hannover.de/twiki/bin/view/GRASS/WebHome


One thing to realize is that GRASS was historically a raster based GIS 
while Arc was a vector based GIS. So GRASS's imagery and grid operations
are very mature. Only with the latest release (6.0) has GRASS had a
very strong vector engine too, so documentation and fine tuning for 
vectors is still just arriving weekly.


> The biggest stumbling block for me was, believe it or not, setting up
> the GISDBASE, LOCATION & MAPSET.  once i got that understood stuff
> started falling into place for me.


The hardest part of GRASS used to be installing it. Now this has moved 
on to being the opening screen. Progress!


Some recommended reading:

"GRASS Quickstart" by M. Neteler  (in the GRASS help pages)
http://grass.ibiblio.org/grass61/manuals/html61_user/helptext.html


"Visual Tutorial for GRASS 6" by L. Moretti  (for non-UNIX people, GUI)
http://wwwamb.bologna.enea.it/forgrass/documents/Grass-6-Visual-Tutorial.pdf


"Open Source GIS: A GRASS GIS Approach. 2nd ed." by M. Neteler and 
  H. Mitasova  (Book; GRASS 5 but non-vector/sites chapters still valid)
http://mpa.itc.it/grassbook2


"An introduction to the practical use of the Free Geographical 
  Information System GRASS 6.0" by GDF Hannover
http://www.gdf-hannover.de/lit_html/grass60_v1.1_en/


More GRASS documentation and tutorials:
http://grass.ibiblio.org/gdp/index.php


> Also, is there a more thorough explanation of what v.digit can do other 
> than http://grass.itc.it/gdp/html_grass5/html/v.digit.html ?  v.digit
> seems quite powerful, and i compare it to ArcEdit (by nature of being
> schooled in the "workstation" approach to GIS).  I recognize i can and
> should RTFM, but being so ingrained in that OTHER software's approach,
> it often messes with my thought process, as i often try to relate
> commands from one software's approach to another, which is probably
> not the best thing to do.

It is poorly documented, perhaps the GDF Hannover guide covers it?
It is very good for fixing broken nodes etc. Still many wishes & fine
tuning need to be done before it will be a really strong program, but
the base is there. As others have mentioned, QGIS+GRASS does well as a
substitute.

 
> some examples are:  
> digitizing/editing topologic vector data

v.digit or QGIS+GRASS

> rectifying images

i.points, i.target, i.rectify.  Or use gdalwarp from gdal.org

> working with GIS vector database attributes (i.e. table manipulation
> and changing attributes)

see the various GRASS 6 tutorials, e.g. this one:
  http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassSixTutorial
(I'm pretty sure there was more to that which hasn't been put in the Wiki 
yet??)

> overlaying vector data with attribute information
 
 - 'd.vect display=attr'
 - v.label + d.paint.labels (improvements in active development)

> cut/fill operations

 - v.overlay, v.select, v.extract, et al.
 - v.to.rast
 - MASK raster maps and r.mapcalc

> cartographic operations for hardcopy maps

 - ps.map can make really nice output (once you learn how)
 - export to GMT for journal quality figures 
  http://gmt.soest.hawaii.edu/
  http://169.237.35.250/~dylan/grass_user_group/#GMT_and_GRASS-overview

 
> Its probably a silly question.  But often times i find my self saying
> "i know how to do this in workstation, I know GRASS can do this, but
> how do i proceed?"

GRASS is very powerful at the low level, so with any task the 
functionality usually exists in GRASS, it's just a matter of figuring 
out how/where to look. Side effect of this is that one of GRASS's real
strong points is its ability to run scripted.

> anyone else out there transition from that OTHER software company to
> GRASS? and what was the best way you handled the migration?  I cant
> totally throw out everything i know about workstation, but cause the
> concepts are the same.  its the specific commands and methodology that
> often have my head spinning...

Just takes time....

> cheers to all users and developers!  GRASS is an amazing piece of GIS
> software!

I agree!

be sure to try NVIZ too.



Hamish