[GRASSLIST:1485] Re: A different problem with v.in.mif

Rich Shepard rshepard at appl-ecosys.com
Wed Feb 21 09:44:21 EST 2001

On Tue, 20 Feb 2001, Eric G. Miller wrote:

> Nope.  I tried you files. Same result.

  Phew! It's not just me. Good. :-)

>  Among the things I noticed: No category file seems to be written, the
> program just exits silently if you don't specify a log file.  For this
> particular file, there seems to be alot of misplaced area attribute
> markers (not unusual with these darn non-topological spatial graphics
> files...) -- apparently a few islands too.

  I'll take a look again at the original. These data come from a prospective
client and I need to get them into GRASS as a "proof of concept" that GRASS
is the platform for their environmental decision support system. Therefore,
it's rather important to me.

  The data were in terrible shape when I got them. That's why there are now
5 separate files for this one theme: I kept removing overlaps into separate
files. However, ... come to think of it ... there were three pairs of
identical objects with completely different attribute records. I'll look
into that today.

  There should be no islands there; objects can be adjacent (with a common
boundary), but each is a discrete rectangle. It could be that the lack of
category file is caused by two attribute records for a single spatial area.

  I will say that this is the worst-formed data I've dealt with in many
years. So, I'll work more with it in MapInfo and see if I can find the
problems there. Based on what you found, I suspect that that's where the
problems lie.

> This is a very new module, so I'm sure David will be working on it
> more...  The conversion of these graphics type files to arc-node is hard
> to do well, while the reverse is easier.

  I know full well. That's why David did all the heavy lifting on this. And
I am grateful for his efforts. If we can discover what makes the module fail
in a translation we can be more explicit about the condition of the data
before translation.

  I'll also try another file from this set: the Public Land Survey System
grid (Township, Range, Section). That _should_ be a lot cleaner.



Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
              Making environmentally-responsible mining happen. (SM)
            2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
 + 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshepard at appl-ecosys.com

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