[GRASS-dev] 6.4.0 blocker bugs

[Paul Kelly]

Hi Maciej, Markus,

On Sat, 15 May 2010, Markus Neteler wrote:

> On Sat, May 15, 2010 at 2:53 PM, Maciej Sieczka <msieczka at sieczka.org> wrote:
>>
>> OK now, so this was actually a revert of a massive update which broke
>> things.
>
> Right - personally, I find it to be a major problem that we are out of
> synch with GDAL now.

I agree it's rather unfortunate. But I think we would be getting a lot 
more complaints and bug reports if we had kept in-sync; the way GDAL now 
handles datum transformation parameters by forcing a default choice just
isn't very desirable for the case of a user setting up a new location.
Having a potentially non-optimal choice being automatically made for them 
could come back to haunt them in the future, perhaps even years into the 
future.

>> Anyway, my point is that gcs.csv as it is now in all GRASS SVN branches
>> lacks towgs84 definition for Pulkovo 1942(58) datum, which results in
>> locations created from EPSG codes [4] lacking it too. The towgs84 should
>> be as in [5].
>>
>> @Markus, Paul
>>
>> Do I simply modify gcs.csv alone or should this be a somewhat bigger change?

GRASS already has the correct parameters for Poland. The problem is that 
it doesn't recognise the datum name "Pulkovo_1942_58"; it is looking for 
"Pulkovo_1942". I would recommend the patch below for working around this 
problem. In 7.x I hope to change things around so we can try to work with 
GDAL's new way of doing things, rather than trying to work around it.

Does this sound acceptable for now - in particular are there any 
differences between Pulkovo 1942 and Pulkovo 1942 (58) that are worth 
worrying about?

Paul

Index: lib/proj/convert.c
===================================================================
--- lib/proj/convert.c	(revision 42262)
+++ lib/proj/convert.c	(working copy)
@@ -744,6 +744,8 @@
      "Militar_Geographische_Institut",
      "Potsdam_Datum_83",
      "Deutsches_Hauptdreiecksnetz",
+    "Pulkovo_1942_58",
+    "Pulkovo_1942",
      NULL
  };