[gdal-dev] unable to open DGN

[Andre Vautour]

On 2015-11-23 12:00, Even Rouault wrote:
> Le lundi 23 novembre 2015 16:48:48, Andre Vautour a écrit :
>> Right, thanks, I wasn't thinking of that when I wrote my reply.
>>
>> Guess it makes sense for a closed format such as DWG. Might not make as
>> much sense to use it for DGN which is more open
> DGN v8: open ? If you have pointers to a spec, I think that would be much
> appreciated by a lot of people...
I apologize, clearly I am not thinking straight today. What I meant to 
say is that Ivan made me realize why the DGN driver was probably not 
implemented by using DGNDirect or Teigha: there was some sort of spec 
available: http://dgnlib.maptools.org/dgn.html.

So, I agree that if using an Open Design library to support such a 
format can be avoided, it would make sense to do so, given their 
licensing. Like I said, I wasn't thinking of that when I first replied.

Kind regards,
André

>> and does not need to be
>> reverse engineered.
>> André
>>
>> On 2015-11-23 11:41, Ivan Lucena wrote:
>>> Just a comment on that: In order to build the DWG driver, you or your
>>> company, need to be part of some kind of alliance to be able to download
>>> a full version of the Teigha SDK. AFAIK
>>>
>>> ________________________________________
>>> From: gdal-dev <gdal-dev-bounces at lists.osgeo.org> on behalf of Andre
>>> Vautour <andre.vautour at caris.com> Sent: Monday, November 23, 2015 9:58
>>> AM
>>> To: Brad Hards
>>> Cc: gdal-dev at lists.osgeo.org
>>> Subject: Re: [gdal-dev] unable to open DGN
>>>
>>> On 2015-11-20 17:40, Brad Hards wrote:
>>>> On Fri, 20 Nov 2015 02:20:55 PM Martin Landa wrote:
>>>>> I am trying to open sample DGN file, but it fails. I guess that the
>>>>> reason is unsupported version (man pages says: Microstation DGN files
>>>>> from Microstation versions predating version 8.0 are supported for
>>>>> reading.)
>>>> As I understand it, version 8 is completely different.
>>>>
>>>>> Is there any possibility how to read this file using GDAL library?
>>>> AFAICT, not unless you figure out version 8 format and implement it, or
>>>> pay someone to do that work for you.
>>> I just want to add that Teigha, which can currently be used to open DWG
>>> in GDAL, does support DGN version 8. So, if someone wants to add that
>>> support, I'd suggest looking at the DWG driver.
>>>
>>> The DWG driver has:
>>> class OGRDWGServices : public ExSystemServices, public ExHostAppServices
>>>
>>> You'd need to have something like:
>>> class OGRDGNServices : public OdRxSystemServices, public
>>> OdDgHostAppServices
>>>
>>> I would not be surprised if considerable chunks of the DWG driver could
>>> be generalized to work for both DWG and DGN,
>>> André
>>>
>>>>     Is it possibly to get the originator to
>>>>
>>>> provide it in some other format (e.g. DXF, noting that will lose the
>>>> georeferencing)?
>>>>
>>>> Brad
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