[GRASS5] Re: GRASS and GDAL

[Frank Warmerdam]

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 at 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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