[GRASS5] Let's release 5.4 asap

[Paul Kelly]

Hello Helena

On Mon, 4 Oct 2004, Helena wrote:

>> On Sun, 3 Oct 2004, Paolo Cavallini wrote:
>> 
>>> Sorry, but I do not see your point (I may be naive): why should I use 
>>> 5.3
>>> instead of 5.7? I cannot afford missing the new vector functionalities, 
>>> and I
>>> think few professional gis users could, nowadays.
>>> So why exactly we could not recommend 5.7 straight away?
>
> even more important argument against widespread use of 5.7 for non-developers
> is that there are still changes/additions that need to be made that affect 
> location
> set-up. In particular, I have just started to test the nviz support for 
> volumes,
> as well as the volume interpolation and the issue of 3d region has poped-up 
> right away.
> I think that if we want to release 5.7/6.0 as 3D GIS the 3d region should be 
> mandatory
> (created when a new location is defined)
> and vertical datum info should be added to coordinate system definition file.

I was just wondering if you have had any more ideas on how vertical datum 
information should be interpreted and what modules would pay attention to 
it, e.g. vector z values, how could a raster layer be tagged as elevation, 
etc.

I think there is a feature in the 5.7 v.proj where the z value (for 3-D 
vectors) is interpreted as ellipsoidal height and transformed during a
re-projection. For this I suppose it might be appropriate to have the
vertical datum associated. But as far as I know the methods for transforming
between vertical datums are all based on localised grids and it probably
would not be feasible to include them all in GRASS.


> If this is adopted, when a user starts 5.7 with old location created by 
> pre-5.7 GRASS,
> user can be asked whether the 3d region file should be created automatically
> (e.g. using the default region with 1 layer and 0 vertical origin.) and in 
> that way
> the old LOCATIONS can be brought up-to-date for 5.7.
> It will be less confusing to make this transition to 3D between 5.3 and 5.7,
> where everybody expects significant differences than later.

That is a good idea. I think it is no problem to make these kind of 
changes one at a time in the 5.7.x series, before 5.8.0 stable is 
released.

> Regarding the sites format - I would very much ask people who use sites to 
> try to
> work without the sites ascii format and use the point data in vector format
> to find out whether it makes sense to abandon the ascii sites format or 
> whether
> there is a serious argument for keeping it. As I mentioned long time ago, the 
> ascii
> sites format was a temporary solution until a better support is available in 
> vector format.
> But apparently it persists due to its convenience (or that we are just used 
> to it).

I think it is a mixture of both. But I know from e-mails to the list that 
the default DBF format has problems dealing with attributes for large 
numbers of points in a vector file, that the sites format would have no 
trouble with, just churn through them all and get there in the end. I 
think the sites format was really well implemented, looking through some 
of the old source code by Bill Brown et al it seems he had some very clear 
ideas about leveraging the simplicity of the format for maximum 
convenience, if that makes sense. I feel confident that there is not a lot 
that can go wrong when using sites.

> As I said months before, I believe that 5.3 should be closed to new 
> development
> and I agree that it should be released as 5.4 ASAP (it is certainly more 
> stable than
> the previous versions of GRASS) and all developemnt should focus on 5.7, but 
> it looks like
> that is happening

Yes I think it is. There is a lot more development in 5.7 now and 5.3 is 
just being tidied up. In fact, thanks to Scott Mitchell letting me use his 
Mac OS X machine for testing, we may have the problem with shared 
libraries on that platform fixed. Things may be ready for 5.4.0 by the end 
of the week at this rate :)

Paul