[gdal-dev] GML3 wrong result for some kind of fields

[Even Rouault]

Le dimanche 24 juillet 2011 12:20:38, Andrea Peri a écrit :
> Hi,
> 
> I notice that the GML driver wrong to understand some kind of field.
> 
> for example:
> 
> I have this tags:
> 
> <element>
>   <id>1</id>
>   <code>010206</code>
> </element>
> <element>
>   <id>2</id>
>   <code>100206</code>
> </element>
> 
> the GML driver parsing this tags intepret they as integer so in the
> shapefile result
> they are translate in
> 
> id (integer), code (integer)
> 1, 10206
> 2, 100206
> 
> this is a bad situation for me because the values in code field is a
> block-code to fixed lenght (6 characters).
> And after the conversion in shapefile is not possible to join with tables
> where there is the values (text) 010206, 100206

Quote of http://gdal.org/ogr/drv_gml.html :

"When prescanning the GML file to determine the list of feature types, and 
fields, the contents of fields are scanned to try and determine the type of the 
field. In some applications it is easier if all fields are just treated as 
string fields. This can be accomplished by setting the configuration option 
GML_FIELDTYPES to the value ALWAYS_STRING."

> 
> I see the GML driver create a .gfs field where it has the description of
> these fileds,
> I could change it, but unfortunately I have many files and to change all
> the gfs is a huge work.
> 
> I think perhaps a good solution should be to use a config parameter to
> overlap the description in the gfs files.
> So I could manually write a GFS file usable for all the files GML I need to
> translate in shapefile/postgis.
> 
> But I don't know if the gfs file do something else or only the description
> of every field.

Yes essentially that, plus the layer name, and optionnaly its extent, the type 
of the geometry, the number of features, etc... 

Another alternative is to provide a .xsd file.

> 
> 
> thx,