Date: Mon, 25 Oct 93 11:00:04 PDT
From: sue@ced.berkeley.edu (Susan Huse)
Message-Id: <9310251800.AA04641@ced.berkeley.edu>
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To: ggjns@knuthmtsu.edu
Subject: Re: Possible bug in v.in.dxf?
From: ggjns@knuth.mtsu.edu (John N. Schmidt)
Subject: Possible bug in v.in.dxf?
Hi there. I have a data set that I have converted from my AGIS GIS
program to a DXF formatted file. The file consists of vectors which
represent several hundred closed polygons. The problem is that for the
life of me I cannot get them imported into Grass via v.in.dxf as
anything but lines, not as areas.In discussions with the people who wrote AGIS, they have checked and
rechecked the DXF export program up and down and say that it conforms
exactly to the DXF specification set out in the AutoCAD manuals. In
fact, I have imported these polygons into AutoCAD Release 11 and they
too come out as closed polygons, complete with area values and the whole
nine yards. Exporting though from AutoCAD to its own DXF format file
puts a whole lot more headers and defined values into the DXF file, but
the results are the same when inputting into Grass 4.1, and running
v.support. Everything is still lines and nodes, but not areas.
What I would suggest is taking the GRASS vector file you have created and
exporting it to ascii (v.out.ascii). Then going directly to the ascii
file and changing all "L"s to "A"s. The format of the ascii file is
an L for lines and an A for areas, followed by the points that make up
the feature. (lower case l's and a's are for deleted areas and lines).
If vi you can go a global replace of L with A. (:g/L/s//A/g)
Then reimport the vector file (v.in.ascii).
I have done this procedure many times (for different reasons) and
have never had a problem.
Good luck
-Sue Huse
CEDR - REGIS
UC Berkeley