[gdal-dev] Using GDAL/OGR/OGDI to read ArcInfo road networks

[Frank Warmerdam]

Ben Discoe wrote:

> 
> Hi Frank,
> 
> I am trying to figure out how to get some data into GDAL/OGR..
> 
> I am encountering users who use ArcInfo for road networks. I'd like to be
> able to read these roads, with topology intact, into the VTP software, via
> OGR.
> 
> If they export the roads, as arc Shapefiles, then the topology is lost,
> since Shapefiles aren't capable of it.
> 
> So, i think i need to read the Arc coverage directly - which is quite a
> number of small files, with extensions like .adf, .dir, .dat, .nit.
> 
> Looking at the OGR documentation, i believe i need OGDI. So, i downloaded
> the OGDI source and built it.
> 
> Next, i presume i'll need a version of GDAL/OGR with OGDI support turned on.
> You just released a binary (gdal-115a-ntbin.zip) with that feature enabled,
> but it lacks the headers/import library. Do i need to build GDAL myself,
> with OGDI enabled? If so, how?
> 
> Presuming that is resolved, what would the next step be? I read the OGDI
> documentation, but it's not clear how to use it. The files are local; do i
> really need to provide a "gltp://" path just to load a local file?


Ben,

A few issues:

o The Arc/Info binary translator in OGDI is a commercial adapter from
Global Geomatics - it isn't free. You might want to ensure the pricing
would be acceptable before going too far.

o I can provide import libraries and include files for the last release
quite easily if you want. I ommitted them to trim the download size.

o To build GDAL with OGDI support, you should just need to uncomment and
correct the definition of the three OGDI macros in gdal/nmake.opt.
However, you also need an OGDI distribution built from source to build
and link against.

o Finally, if you did read arc/info vectors through OGDI and/or OGR you
are only going to get the topological connections as an attribute of
some kind. Neither OGR nor OGDI inherently support topological vectors.

Best regards,

-- 
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I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at p...
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