GRASS is very cautious with regards to upgrades--some would say too
cautious. Great care is taken to maintain all backward compatibility
within a version. That is, code written for version 6.0 should run on
version 6.4rc5.
However, the program needs to evolve too. This happens between major
version numbers. For example, the vector file structure changed
dramatically between version 5 and 6--for the better AFAIC because it
made for the default link between vector objects and attribute tables.
But this still will break some scripts.
Between 6 and 7 there will be changes to the raster file structure.
Also, the display architecture is being cleaned up a lot. A great many
GRASS modules called in scripts dating from version 4 will still run
in version 7. You can translate files created in version 4 to version
7. One of the changes in 7 is to get rid of an old interactive mode
that affected a subset of the d* modules. This mode has restricted
GRASS to a tiny fraction of the computers used by people today. I'm a
die-hard Mac user and I like Linux, but I realize that even together,
these constitute a small proportion of the OS used by people across
the world. Even for me, running d.mon and d.rast was handy, but this
is easily replaced. The interactive parts of d.measure, d.zoom, etc
have been replaced by an alternate way of interacting with a mouse.
Scripts which depended on these for interaction were depending on an
interaction mode and display architecture dating to the 1980's. In
"computer years", that must be at least a century or two ;-) It's
amazing that GRASS has maintained that architecture so long, but it
has done so at increasing cost for functionality and access by users.
The changes in architecture with version 7 have been discussed on the
dev list and in the WIKI for over two years.
The point is that to me at least this seems like a LOT of stability
for computer software. Recently, I discovered some files that I had
forgotten to upgrade from Microsoft Word ver. 3 in the early 1990's.
So far, I have not been able to find anything to read these files. A
GRASS file from that era can be read and many scripts written in that
era will still run. Most of those that won't run can be made to do so
with minimal tweaking. At the same time, GRASS has been modified to
also work with a wider variety of scripting languages, with a special
emphasis on Python--an easy to use open source language widely used in
the sciences. So IMHO your advice to the client is not at all off the
mark.
Michael
On Dec 5, 2009, at 2:11 AM, Vincent Bain wrote:
Le vendredi 04 décembre 2009 à 14:16 -0700, Michael Barton a écrit :
Markus,
This is helpful. Much more so than simply those that ask 'why can't
we
do things the way we did'.
Michael,
as far as I am concerned by your remark, I just wish to distinguish my
attitude from that of a potential pure fastidious/demanding
consumer : I
just keep very cautious from giving "advices" when I feel like being a
too modest contributor...
To finish off with my contribution, I initially bewailed the loss of
some functionalities that straightly threatened some home-made
pieces of
code I use daily and intensively.
I rencently worked for a customer who needed to upgrade a series a
ArcInfo AML routines I wrote for him some years ago for AI7.2 and
which
did not work properly now on AI9. I praised him that developing his
future personalized solutions on GRASS would be a guarantee of
long-lasting, reliabilty, and so on... oops !
Vincent
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