[GRASS5] Re: GRASS and GDAL

Markus Neteler wrote:

Hi Frank,

I have seen that your GDAL is included in OSSIM and
OpenEV software.
We still face the problem that GRASS lacks an
intuitive user interface.

As I am involved in the team, I am thinking how
GRASS can be improved for a wider usage. Question
is if we should write a new user interface or
perhaps merge the GRASS functions into another
project. GRASS should have the LIMP library for
raster processing. I am shure this is a non-trivial
task.

Do you have recommendations for me?

Markus,

Well, I took the contract with Atlantis Scientific as a result of my posting
in December, or January about the need for a modern viewer application for
GRASS. So, I do hope that OpenEV could be a useful basis for a GRASS viewer
though I have since come to doubt the wisdom of depending on OpenGL. OpenEV
is very OpenGL dependent, and even software implementations like Mesa can
make performance somewhat painful.

That aside, I still hope to integrate support for GRASS raster, and vector
data into GDAL, and to therefore be able to use OpenEV as a GRASS data viewer.

OpenEV is built with Python as the extension language. I think it would be
_relatively_ easy to make menus and so forth for OpenEV using python that
would launch GRASS analysis progress in the background, but I haven't analysed
that issue in detail.

OSSIM might also be a useful viewer. It is much less far advanced at this
time, but it doesn't currently have a dependency on OpenGL which is a plus
for portability.

I am not sure why you want to incorporate LIMP. It isn't maintained much
now, and it is mainly useful as a high performance environment to implement
filters, and other image processing operators in.

So, in summary, in the short term, I would like to work with the GRASS
community to make OpenEV a useful GRASS data viewer; while leaving execution
of analysis programs to the commandline (as now). If this effort is
reasonably successful, then it would make sense to pursue a closer
integration, where GRASS analysis programs can be launched from OpenEV.

A few weeks ago, I was asking about the raster access code for GRASS
in the hopes of extracting it for incorporation in GDAL. I haven't
pursued it since, but perhaps this would be a good time to revisit it.

There was an issue about the license. I think the easiest way to avoid
this issue is for me to extract the code from the last non-GPL release.
Is that 4.3? I would like to prepare a relatively minimal C library
which can be used without the rest of GRASS for other applications to
read, and write GRASS data (initially just raster, but later vector). I
would integrate this into GDAL, but it would also be available for other
applications that want GRASS compatibility, but don't want to incorporate
all of GDAL to get it.

Does this seem like a worthwhile project?

Unfortunately, GRASS support isn't mandated by Atlantis Scientific, so I
think I will have to go ``off the clock'' while I work on it.

You are free to redistribute the above to the list or whereever
as you please.

BTW: GRASS offers datum transforms in the next release.
Andreas Lange wrote a set of transforms based on
old code already existing in GRASS.

Yes, Andreas and I have been in contact on an off about this. It seems
like a pity not to share a unified PROJ.4 based implementation, but it's not
a big deal.

Best regards,

---------------------------------------+--------------------------------------
I set the clouds in motion - turn up | Frank Warmerdam, warmerda@home.com
light and sound - activate the windows | http://members.home.com/warmerda
and watch the world go round - Rush | Geospatial Programmer for Rent

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Frank:

I don't know GDAL, but some of the same things were needed in the latest
version of the R/GRASS interface, essentially to include gis.h, and link
against functions in libgis.a. The tarball is at:

ftp://reclus.nhh.no/pub/candg/GRASS_0.1-3.tar.gz

and the source files are in GRASS/orig/src

In the README you will find mention of gotchas in libgis.a which hit
exit() without using the documented error handler - Markus is merging my
changes into the CVS repository under libes/gis.

I have thought that it might be neat for a subset of the libraries and
header files to be put my make install in lib and include directories
under $GISBASE, so that other programs can find them.

Roger

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no
and: Department of Geography and Regional Development, University of
Gdansk, al. Mar. J. Pilsudskiego 46, PL-81 378 Gdynia, Poland.

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Hi Frank, [cc to GRASS 5 developers list]
hi GRASS developers,

On Tue, Jul 04, 2000 at 12:18:31PM -0500, Frank Warmerdam wrote:

Markus Neteler wrote:
> > OpenEV is built with Python as the extension language. I think it would be
> > _relatively_ easy to make menus and so forth for OpenEV using python that
> > would launch GRASS analysis progress in the background, but I haven't analysed
> > that issue in detail.
> This sounds very good as Python may be a good way to reach portability
> between UNIX/Linux and Windows world. We still hope to get GRASS
> running on all platforms. John Huddleston added numerous patches to
> GRASS, now the analysis tools run on Windows/Cygnus, the XRRIVER
> port is still in progress.

Markus,

Certainly Python should not be a barrier to portability, but using Cygwin it
seems that the XDRIVER stuff would be your main portability problem.

Yes, you are right. I hope that the XDRIVER port can be finalised
soon :slight_smile:

> > OSSIM might also be a useful viewer. It is much less far advanced at this
> > time, but it doesn't currently have a dependency on OpenGL which is a plus
> > for portability.
>
> Well, what about Imagelinks? Is it for shure that OSSIM will be kept
> in open source in future? I do not want to spend my time for others
> and finally get no access to the code later on. Maybe this is somewhat
> pessimistic?!

The code is public now, and under GPL / LGPL so there isn't anything they
could do to retract it. Of course, I think there is a substantial risk that
they will abandon work on OSSIM at some point, perhaps before it is at a very
useful state. Of course that risk exists with OpenEV as well.

> > I am not sure why you want to incorporate LIMP. It isn't maintained much
> > now, and it is mainly useful as a high performance environment to implement
> > filters, and other image processing operators in.
> Well, I thought it would help to speed up zooming etc. within
> a GIS when using large datasets. I do not know enough about LIMP.

It does handle this well, but if you are mainly concerned about display
speed for overviews of images there are other ways of achieving good
performance. Certainly this is a key aspect of OpenEV, and I have done
substantial work on GDAL to support pyramiding to help accelerate OpenEV.

Yes, pyramiding could be a useful approach to speed up the raster
management. Maybe it can be included into the GRASS raster libes,
then we do not need the LIMP.

> > So, in summary, in the short term, I would like to work with the GRASS
> > community to make OpenEV a useful GRASS data viewer; while leaving execution
> > of analysis programs to the commandline (as now). If this effort is
> > reasonably successful, then it would make sense to pursue a closer
> > integration, where GRASS analysis programs can be launched from OpenEV.
>
> You are very welcome. It would be a good idea to put this on
> a web page within GRASS server to get more people involved.

I will promote OpenEV on the GRASS web page, and mailing list if/when I
get a GRASS link completed.

Please let me know when finished, then we add a page here.

> > There was an issue about the license. I think the easiest way to avoid
> > this issue is for me to extract the code from the last non-GPL release.
> > Is that 4.3?
>
> Well, what is the problem with license? I think as GRASS is GPL'ed, you
> may use it and integrate it into GDAL. Note: The 4.x stuff does not have
> floating point support. So you should go and use the current CVS
> version. The libraries are in src/libes/, the includes in src/include/

The problem is that GDAL is not GPL. It is under a less restrictive MIT
license. In order to link in GPL code, I have to make all of GDAL GPLed.
However, since you point out that the 4.3 code is significantly behind the
5.0 code (re: floating point) I will work from the 5.0 code. If possible
it would be nice to put the code I extract under LGPL, for which I would
need the permission of the current copyright holder (you? Baylor?). If
I can't do this, I will still provide the GRASS library as a separate
package, but I won't be able to distribute it as an integrated part of GDAL.

Well, Baylor did not contribute to GRASS 5 source code since last summer.
So the current developers are the copyright holders (at least I should
belong somehow to the copyright holders). Anyway, I think we could
discuss to release the GRASS libraries under LGPL. As we want to
modularize the code into packages, this should not be a technical
problem.
So, GRASS developers: What's your opinion here? Any problems to put the
GRASS libs under LGPL?
Then it should be compliant to GDAL and reduce barriers.

> > Unfortunately, GRASS support isn't mandated by Atlantis Scientific, so I
> > think I will have to go ``off the clock'' while I work on it.
>
> Mhhh - maybe we get them interested to support GRASS? Like
> Imagelinks supports OSSIM?

Well, it was something to get them to agree to OpenSource OpenEV. I can't
see a credible way of convincing them that GRASS support is a worthwhile
expenditure of their limited resources.

O.k. If they support OpenEV and this could become a useful GUI for
GRASS once, we have the same result. Of course GRASS is open to
other GUI's as well - no restrictions.

(BTW: http://openev.sourceforge.net/)

> I do not know details here, but maybe it can be unified again. Then
> PROJ4 could be included like a plug-in into GRASS and updated easily.
> As you are interested in datum transforms as well, the wheel should not
> be re-invented.
I don't think it is a big issue.

Thanks for your comments,

best wishes

Markus Neteler

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So, GRASS developers: What's your opinion here? Any problems to put the
GRASS libs under LGPL?

I am all for this license change, personally. It fits in better with the
original relase concept of "public domain". As an occasional contributor, I am
happy to see my code be used elsewhere.

Most of the improvements to GRASS will continue to be rolled back in by
contributors, and will be made available to the GRASS community.

If there is a licensing issue associated with doing an Open Source (but not
GPL-compatible) project, we should change our licensing conditions, if only to
allow further usage of GRASS, which can only be good for us, the GRASS
community.

Angus Carr.

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On Tue, Jul 04, 2000 at 06:12:05PM -0400, Angus Carr wrote:

> So, GRASS developers: What's your opinion here? Any problems to put the
> GRASS libs under LGPL?

I am all for this license change, personally. It fits in better with the
original relase concept of "public domain". As an occasional contributor, I am
happy to see my code be used elsewhere.

Even if it is improved and then closed up. :slight_smile:

Most of the improvements to GRASS will continue to be rolled back in by
contributors, and will be made available to the GRASS community.

Well histroy shows, that this was not the case, so the better protection
of the GPL is necessary in my opinions.

If there is a licensing issue associated with doing an Open Source (but not
GPL-compatible) project, we should change our licensing conditions, if only to
allow further usage of GRASS, which can only be good for us, the GRASS
community.

It could snap back as it did in a couple of times.
(Commercial comanies taking code, GRASS for windows, gpz's improvements).
GRASS sufferent from a long track of people taking code and not
contributing back again.

However I believe that we should make the libraries which deal with
interoperabilty available under LGPL. Frank want access to the GRASS
data file structures, we should seperate that part of the GRASS
libraries and release it under the GNU Lesser General Public License
(LGPL).

And of course we all know that Frank Warmerdam's intentions are good and
he is a great contributor to free software. Frank: Can you identify the
library (parts) of GRASS, you need for accessing grass files? It should
be as small as possible. We should to get consensus to release this part
under LGPL.

  Bernhard
--
Professional Service around Free Software (intevation.net)
The FreeGIS Project (freegis.org)
Association for a Free Informational Infrastructure (ffii.org)

Hi GRASSdevelopers,

i agree with Bernhard. The required parts of the libararies should be
made available under LGPL, but only those parts that are absolutely
required. We should bear in mind what consequences loosening the
copyright could have.

cu,

Andreas

Bernhard Reiter wrote:

However I believe that we should make the libraries which deal with
interoperabilty available under LGPL. Frank want access to the GRASS
data file structures, we should seperate that part of the GRASS
libraries and release it under the GNU Lesser General Public License
(LGPL).

And of course we all know that Frank Warmerdam's intentions are good and
he is a great contributor to free software. Frank: Can you identify the
library (parts) of GRASS, you need for accessing grass files? It should
be as small as possible. We should to get consensus to release this part
under LGPL.

--
Andreas Lange, 65187 Wiesbaden, Germany, Tel. +49 611 807850
Andreas.Lange@Rhein-Main.de - A.C.Lange@GMX.net

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