Hi Grassusers and developers,
could someone explain me what's the difference between fp and non-fp
versions ?.
I think it is a kind of essential question for a new user of GIS.
thanks a lot,
swalt.
***********************************************
Walter Finsinger
Unversitaet Bern - Botanische Institute
Geobotanisches Institut
Altenbergrain, 12
CH-3013 BERN
Tel.: ++41-(0)31-631 49 25
Fax: ++41-(0)31-332 20 59
Hi Walter,
the GRASS 4.x versions are non-fp,
the GRASS 5.x versions support fp.
FP means: Floating point support in raster format.
GRASS 4.x can only save integer numbers in raster
format, GRASS 5.x additionally stores floating point
numbers. This is quite interesting to store e.g.
full ranges of angles (slope, aspect), height
information etc.
Other new features in GRASS 5.x are:
- new sites format (to store multiple dimensions and attributes)
- voxel raster format (grid3D)
- DateTime library to have timestamps for raster and sites maps.
- NVIZ visualization tool
- recently: SQL support and interface to "R" statistical language
While GRASS 4.3 is the stable GRASS version (non-fp), the
"beta" GRASS 5.x offers more features but some bugs as well.
GRASS 5 is under heavy development. Most of the raster and
site modules are updated for fp support now, but a few modules
are still missing/not working. The latest version you
get from the GRASS-CVS repository.
Hope this helps
Markus Neteler
University of Hannover
Physical Geography and Landscape Ecology
Schneiderberg 50 * D-30167 Hannover
Tel: ++49-(0)511-762-4494 Fax: -3984
----------------------------------------
On Sun, Mar 26, 2000 at 03:20:55PM +0200, Walter Finsinger wrote:
Hi Grassusers and developers,
could someone explain me what's the difference between fp and non-fp
versions ?.
I think it is a kind of essential question for a new user of GIS.thanks a lot,
swalt.
***********************************************
Walter FinsingerUnversitaet Bern - Botanische Institute
Geobotanisches Institut
Altenbergrain, 12
CH-3013 BERN
Tel.: ++41-(0)31-631 49 25
Fax: ++41-(0)31-332 20 59
On Sun, 26 Mar 2000, Walter Finsinger wrote:
could someone explain me what's the difference between fp and non-fp
versions ?. I think it is a kind of essential question for a new user of
GIS.
Walt,
The major difference is where the decimal point (or comma for those of you
in Europe) is placed.
Suppose you have a sites file with soil nitrogen levels measured in an
agricultural field, and you want to build a 3D model of those values. The 3D
surface will allow you to see the distribution of nitrogen over the area of
the field.
In the pre-floating point version you would have to multiply all your
nitrogen values by some power of 10 to make them integers. When you are done
with all the processing, interpolating, analyzing and displaying, you need
to divide the final numbers by the same power of 10 to restore them to the
correct magnitude. A lot of bookkeeping involved.
With the floating point version you avoid that extra work.
On the other hand, not all modules have been ported to the new version 5.
It also has a different file format for data so it may take a while for
everyone to migrate from version 4.x to 5.x.
HTH,
Rich
Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc. (TM)
Making environmentally-responsible mining happen. (SM)
--------------------------------
2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard@appl-ecosys.com