[GRASS5] GRASS development roadmap proposal

[Markus Neteler]

On Thu, Jul 17, 2003 at 05:29:07PM +0200, Bernhard Reiter wrote:
> On Thu, Jul 17, 2003 at 05:08:31PM +0200, Markus Neteler wrote:
> > On Thu, Jul 17, 2003 at 04:36:01PM +0200, Bernhard Reiter wrote:
[...]
> > > > Two problems have to be addresses:
> > > > - in a 5.0.x version we should not introduce
> > > >   datum transformation as the results will be
> > > >   different
> > > 
> > > I did not follow the datum discussions in detail.
> > > What do you mean with: The results will be different?
> > 
> > We should not have 5.0.2 without datum transformation and
> > 5.0.3 with datum transformation as the same commands (*.proj)
> > will end with different results. This means that the maps
> > are shifted up to some hundred meters. Subversions must
> > behave the same.
> 
> Why would the maps be shifted in particular?

The datum transformation is an important feature which was
luckily implemented by Paul Kelly recently (using the datum
transformation routines from PROJ4).

> Is it a systematic error in all versions?

Yes. All official GRASS versions are lacking this feature.

> Or an additonal feature.
> If it is an error, when was it introduced?

In 1984 when GRASS 1.0 was released :-)

Without the datum transformation routines a map re-projection
is less accurate. See for example:
http://mpa.itc.it/markus/tmp/asterdem_test_geotiff_utm_rivadelgarda.jpg
(the orthophoto was reprojected from Gauss-Boaga to UTM without datum
transformation)


> > > > - we should release datum transformation as soon as
> > > >   possible as it is crucial for GIS data processing.
> > > 
> > > Another idea would be to make in an experiemental add-on package
> > > to 5.0.x if the datum transformation support is ready for this.
> > 
> > Yes, but with a different version name. Otherwise there will be
> > too much confusion in the user community ("why is my map
> > shifted...").
> >  
> > > It is clear that the 5.0.x serious has to transform into the
> > > 5.1.x serious which then transforms into 5.2.x at some point
> > > where 5.0.x support hopefully can be discontinued.
> > 
> > In general that the idea.
> 
> ? 

Sorry, should read:
In general it's the idea that 5.0.x support hopefully can be discontinued
in favor of the new developments.
 
> > > The renaming part (5.0 HEAD -> 5.3.0 and 5.1.0 -> 5.7.0) suggested
> > > will cause confusion. I advise against it.
> > 
> > So please make a better proposal.
> 
> Need to know more about the datum transformation situation
> before I can suggest something reasonable.

You may search in the 'grass5' archives, there is a lot of discussion
stored.
 
> Thinking more about it, renaming in a form close
> to your proposal, might be a possible solution.

Fine, so let's continue the discussion. More comments welcome.

My goal is to get out a new release for bugfixes (5.0.3) and
a new release containing the datum transformation and PROJ4
improvements (5.4.0) and probably a first release of the new
vector developments if Radim agrees.

Markus