[GRASS5] Re: [bug #2451] DXF module for GRASS 5.7

Radim,

Your points are well taken. I don't know off hand if it is better to get DXF into OGR via DIME or go another route (e.g., there are a few other translate projects that come up on SourceForge when you look for dxf).

On the other hand, I don't think it is false advertising if we say GRASS supports DXF ver. #-#, or something like that. QCAD uses some version of DXF natively and it would be nice to be able to import QCAD maps. Other CAD programs probably don't keep up with the most current AutoCAD standard for DXF. And can't AutoCAD folks export down-version if need be?

It's just that DXF is a (perhaps THE) widely used standard (even if it is not quite 'standard') for CAD data exchange--and for exchange among GIS programs. GRASS as it is has exceptionally good abilities to read other formats and DXF is one of the few holes in this.

Michael
______________________________
Michael Barton, Professor & Curator
School of Human Origins, Cultures, & Societies
Arizona State University
Tempe, AZ 85287-2402
USA

voice: 480-965-6262; fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton
On Jun 3, 2004, at 1:31 AM, Radim Blazek via RT wrote:

-------------------------------------------------------------------------
On Thursday 03 June 2004 03:07, Hamish wrote:

2. More difficult, but I think important. I'd like to see DXF import
and export modules produced for 5.7. Those in 5.3 have considerable
limitations. 5.7 has overall very good I/O routines due to gdal and
ogr. However, OGR doesn't include dxf. This is a major data
interchange format that I think ought to be supported if possible.

There is v.in.dwg for this, but it needs a non-free library & you must
not redistribute any resulting binaries.

see http://thread.gmane.org/gmane.comp.gis.grass.devel/1205

Have there been any improvements in the Free Software solutions for
DXF importing during the last year?

e.g. libdime
Description: DXF Import, Manipulation, and Export library.
Dime is a C++ class library for reading, constructing, manipulating,
and writing DXF file data.

http://www.coin3d.org/Coin3D/file_format_libs/Dime/

[FreeGIS people: the link on your page is broken]

Is the time better spent getting Dime <=> OGR working?

There is no free DXF library supporting reliably latest DXF.
I see that Dime status has not changed in last years, still:
"... version 10 through 14, and we've had customers that have used the library to handle
AutoCAD 2000 DXF files."
OpenDWG supports DXF/DWG from 2.5 to 2004. My experience is that AutoCAD
users use often latest versions.
Generally, I don't like the idea to pretend that some feature is supported
if we know that it is not true.

v.out.dxf is something else, it is simple and it should be updated
to 5.7, but it should read binary file, not ascii.
It woud be better to have DXF write support in OGR, but I am not sure
if Frank likes drivers which can write only.

Radim

On Thursday 03 June 2004 22:37, Michael Barton wrote:

Radim,

Your points are well taken. I don't know off hand if it is better to
get DXF into OGR via DIME or go another route (e.g., there are a few
other translate projects that come up on SourceForge when you look for
dxf).

DXF/DWG is too complex and changing too often for current size of comunity
which could potentialy create free DXF/DWG library.

On the other hand, I don't think it is false advertising if we say
GRASS supports DXF ver. #-#, or something like that. QCAD uses some
version of DXF natively and it would be nice to be able to import QCAD
maps. Other CAD programs probably don't keep up with the most current
AutoCAD standard for DXF. And can't AutoCAD folks export down-version
if need be?

They can but only some 2 latest versions if I recall well.
I have written here (the last paragraph)
http://grass.itc.it/pipermail/grass5/2003-May/007878.html
why it is not good solution.

It's just that DXF is a (perhaps THE) widely used standard (even if it
is not quite 'standard') for CAD data exchange--and for exchange among
GIS programs. GRASS as it is has exceptionally good abilities to read
other formats and DXF is one of the few holes in this.

No, it can read latest DWG/DXF via v.in.dwg (OpenDWG) which can be used for any
work by any organization. Unfortunately it cannot be distributed with GRASS
and users have to compile it themselves.

Radim