[GRASS5] GRASS Add-ons

[Michael Barton]

Helena,

IMHO, the best solution to this is Benjamin Ducke's new GRASS Extensions
Manager (GEM). This is nearing final release. It allows users to add new
modules (i.e., extensions) in a special extension directory. These will
automatically be added to a special xtn menu in the GIS Manager or (of
course) be accessible via the command line. These can be added to a binary
installation of GRASS.

This way we *CAN* have some kind of control over what goes into a base GRASS
installation AND users can install all the really neat add-ins you're
seeing. Most importantly, they can add these without compiling GRASS.

Michael


On 3/11/06 10:49 PM, "Helena Mitasova" <hmitaso at unity.ncsu.edu> wrote:

> I have a question about Add-ons - Do we have any restrictions /
> official rules for what can go into GRASS add ons?
> 
> http://grass.gdf-hannover.de/twiki/bin/view/GRASS/GrassAddOns
> 
> I noticed that quite a few useful modules are being developed (such
> as the below r.lake)
> and it would be great to have them submitted into add-ons so that
> people can see what
> is available, test it and if it is great and important it could be
> included into next release.
> Also - do we have any rules on when an add-on module can be submitted
> to CVS?
> 
> thanks, Helena
> 
> 
> 
> On Jan 9, 2006, at 9:18 AM, M?ris Nartišs wrote:
> 
>> As my first attempt to contact dev list failed (my mail was eaten by
>> mail daemons ;), I resend my first mail.
>> 
>> 
>> Hi,
>> 
>> I send to You my first peace of C code (after hello world ;). As a
>> newbie I would like to hear any feedback about this code:
>> 1) Is idea worth to be included in GRASS some day?
>> 2) Any comments about programming in GRASS and C in general.
>> 
>> NAME: r.lake (original ;)
>> 
>> PURPOSE: This module fills lake at given level from start point
>> (seed) on DEM.
>> 
>> HOW it works: it assigns depth value to all cells which are connected
>> to start point and are below water level. Filling is done by moving
>> window multiple times (as necessary) across map. Output map depth
>> values are positive, but it is possible to output negative values
>> (units below water surface) for visualisation purposes.
>> 
>> TODOs:
>> - 3d output. Current output is 2d + depth value;
>> - nice blue gradient for output map;
>> - documentation with examples - in progress.
>> - other ideas?
>> 
>> BUGs:
>> - seed map cannot be negative - cannot use negative lake output
>> maps as input.
>> 
>> HOW to use:
>> input = DEM
>> seed = raster with at least one cell below water level with value > 0
>> lake = new output raster file
>> wl = water level in DEM units
>> -n = output map will have negative values
>> -o = overwrite seedmap instead of using "lake"
>> 
>> HISTORY:
>> Last spring I was working on my master thesis and needed way how to
>> find lake shape, depth if only single bank point is known. As I could
>> not find existing method in GRASS, someone on GRASS user list
>> suggested to use r.mapcalc. I wrote script that calls r.mapcalc and
>> fills lake cell by cell. On 3 GHz P4 it took about 24 - 48 h to finish
>> single lake map. This autumn I read "teachyourself C in 24h" and
>> rewrote it in C. Now - after some testing and improving - here it is
>> :) Now I can get my lake in less than minute even on my 800 MHz
>> Celeron :)
>> There has been request from users for such functionality on GRASS user
>> list, so, IMHO after this module will be checked, tested etc, it could
>> be useful for other ppl too.
>> 
>> CHANGES: Added gettext support by Markus Neteler;
>> -o flag = in/out separated.
>> 
>> WBR,
>> Maris Nartiss
>> <r_lake.zip>
> 
> 
> 

___________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Arizona State University
Tempe, AZ  85287

WWW - http://www.public.asu.edu/~cmbarton
Phone: 480-965-6262
Fax: 480-965-7671