[GRASSLIST:3899] Re: m.in.e00: Attaching cat labels to lines.

[Michel Wurtz]

Ben Logan wrote:

> When I import the coverage for the roads in a county, m.in.e00 creates
> the roads.* files in dig_cats just like expected.  However, if I copy,
> for example, roads.route (which contains the route numbers for all the
> roads) to roads, and run v.support, the labels are attached to
> _areas_.  This also matches what v.support says when it is run.  I.e.,
> it says there are 300+ areas, several thousand lines, and 300+ labels.
> 
> I don't think this is a problem with m.in.e00, but I don't understand
> why road numbers would be used as area category labels.  Seems
> perfectly useless to me.  I don't think it is m.in.e00's fault because
> when I import the road data files from the SAA Database, the labels go
> with the lines, and not areas.

m.in.e00 read both area's and line's labels, but it seems that the dig_att
file is reinitialized when one want to add area labels when it contains
line labels, hence erasing all lines' labels :-(
M.in.e00 read lines attributes when creating lines (and creates line labels),
and then reopen it to add area labels if there is a "LAB" section in the
e00 file...
This is generaly not annoying because you are interested by areas... and
because there is no area's labels in a line coverage.
I suspect that the initial design of Grass does not support well mixed
(areas and lines) vector files, because labels are common to areas and
lines.  I also suspect the functions used to manage dig_att files to
forbid partial update...

If you can sent me as a private mail a (not too big) example, I will look
at what's happening : maybe it's a bug easy to correct...

You can also use verbose=9, in which cas you will see the number of
line's and area's attributes read.
You can also look at $LOCATION/dig_cat/<vectorfilename> to see the
attributes (line begins with L for line attributes and A for
area attributes).

--
Michel WURTZ - DIG - Maison de la télédétection
               500, rue J.F. Breton
               34093 MONTPELLIER Cedex 5