[gdal-dev] support for Czech Exchange Format for Land Consolidation

[Even Rouault]

Selon Martin Landa <landa.martin at gmail.com>:

> Hi all,
>
> together with colleague of mine we are thinking to add support to GDAL
> for the Czech Exchange Format of Land Consolidation. This format is
> XML-based, but unfortunately not a GML. Here is a small sample (just
> line segments):
>
>   <zs>
>     <plins>
>       <plin typ="55">
>         <lin>
>           <segment xsi:type="v:se">
>             <c x="1075053.92" y="591813.89" />
>             <c x="1075055.75" y="591793.89" />
>           </segment>
>         </lin>
>       </plin>
>       <plin typ="55">
>         <lin>
>           <segment xsi:type="v:se">
>             <c x="1075055.75" y="591793.89" />
>             <c x="1075059.23" y="591777.01" />
>           </segment>
>         </lin>
>       </plin>
>       <plin typ="55">
>         <lin>
>           <segment xsi:type="v:se">
>             <c x="1075059.23" y="591777.01" />
>             <c x="1075058.48" y="591773.38" />
>           </segment>
>         </lin>
>       </plin>
> </zs>
>
> I wonder if there is an easier way than to write a new GDAL driver
> from the scratch (using XML parser similarly to GML driver)...

Martin,

Although I've always felt intimated by its syntax, I imagine you could write a
XSLT document that would transform the above XML in GML. Easier solution is to
do it off-line (i.e. outside GDAL), otherwise if you want something transparent
to the user, we could have a generic XML driver that would try several XSLT
documents and then feed the transformed document to the GML driver. I don't
think we have already a dependency library that handle XSLT however. In
http://en.wikipedia.org/wiki/XSLT, I see libxslt mentionned as a possibility.
One point to check is if the libraries can do the transform in a streaming way
(SAX parsing) or if they must ingest the whole document (DOM), which could be a
limitating factor for big documents.

If you go with a from-the-scratch driver, I would not recommand to go from the
GML one which has become very complicated. GeoRSS or GPX are probably better
starting points.

Even

>
> Thanks in advance for any idea! Martin
>
> --
> Martin Landa * http://geo.fsv.cvut.cz/gwiki/Landa
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