[gdal-dev] ogr2ogr problem converting UK Ordnance Survey MasterMap

Tue Jul 13 11:51:07 EDT 2010

Jez,

If you don't have any xlinks in your GML files you can skip a bottle-neck by
setting the configuration option GML_SKIP_RESOLVE_ELEMS to ALL. Please note
that this is a quick and dirty fix. The code will change shortly.

On Tue, Jul 13, 2010 at 9:02 PM, Jez Walters <Jez.Walters at ipl.com> wrote:

> Even,
>
>
> My ultimate objective is to read OS MasterMap GML using MapServer, but
> MapServer skips various fields when reading this GML directly.  I don't know
> if this is a fault with GDAL/OGR or with how MapServer is calling it.  In
> order to overcome this restriction, I've been converting the GML to ESRI
> Shapefiles using ogr2ogr.  Fortunately, MapServer appears to have no
> difficulty reading ESRI Shapefiles!  :-)
>
> I've been playing with your latest GDAL code and the '-splitlistfields' and
> '-maxsubfields 1' options let me do this conversion, but it does seem rather
> slow now.  Please don't misunderstand me, but given that GDAL v1.7.2 works
> too without these options it's difficult to see the gain for what I am
> trying to achieve.
>
> Perhaps it would be possible to speed things up by combining the stages
> that produce the '.resolved.gml' and '.gfs' files?
>
>
> Jez
>
>
> -----Original Message-----
> From: Even Rouault [mailto:even.rouault at mines-paris.org]
> Sent: Monday 12 July 2010 22:09
> To: gdal-dev at lists.osgeo.org
> Cc: Jez Walters; 'Martin Daly'
> Subject: Re: [gdal-dev] ogr2ogr problem converting UK Ordnance Survey
> MasterMap
>
> Jez,
>
> if you checkout latest GDAL trunk, you'll find a new -splitlistfields
> option for ogr2ogr that will split fields of type IntegerList, RealList or
> StringList into as many subfields of single type as necessary. You can also
> specify -maxsubfields an_integer_value to limit the number of subfields (can
> be usefull if you just want to keep the first element of the list, or to
> keep the number of subfields to a reasonable number, as some features from
> your GML file have a big number of elements in the list)
>
> Even
>
> Le Monday 12 July 2010 20:04:00 Even Rouault, vous avez écrit :
> > Jez,
> >
> > Yes this is a limitation of the shapefile format (and most drivers,
> > PostgreSQL databases being one of the exceptions).
> >
> > Try adding -fieldTypeToString IntegerList,RealList,StringList to your
> > ogr2ogr command line. This will transform any field of those types into a
> > String field by concatenating the values into a single string (what you
> can
> > see with ogrinfo). Beware that if the list if longer more than a few
> items,
> > there will be a truncation at 80 characters.
> >
> > I'm considering to see if it's practical or not to add an option to
> ogr2ogr
> > to split fields of type *List into several fields of simple type.
> >
> > Best regards,
> >
> > Even
> >
> > PS: For the record, in http://download.osgeo.org/gdal/daily/, you can
> find
> > daily snapshots of the source code of the trunk (1.8.0dev) and the 1.7
> > stable branch.
> >
> > Le Monday 12 July 2010 18:09:16 Jez Walters, vous avez écrit :
> > > Even,
> > >
> > >
> > > I've just rebuilt GDAL/OGR using the latest code from the GDAL 'trunk',
> > > but now I get the following error using ogr2ogr to convert an OS
> > > MasterMap chunk (e.g.
> > >
> http://www.ordnancesurvey.co.uk/oswebsite/products/innovations/sampledata
> > >/O SMasterMap_Topo/58116-SX9192-2c1.gz) into ESRI shapefiles:
> > >
> > > "ERROR 6: Can't create fields of type StringList on shapefile layers."
> > >
> > > The various fields for which this error is reported do not appear to be
> > > in the resultant shapefiles. Unfortunately this makes the new GDAL code
> > > unusable for me.  :-(
> > >
> > > Any thoughts?
> > >
> > >
> > > Jez
> > >
> > >
> > > -----Original Message-----
> > > From: Even Rouault [mailto:even.rouault at mines-paris.org]
> > > Sent: Sunday 11 July 2010 11:12
> > > To: gdal-dev at lists.osgeo.org
> > > Cc: Martin Daly; Peter J Halls; Jez Walters
> > > Subject: Re: [gdal-dev] ogr2ogr problem converting UK Ordnance Survey
> > > MasterMap
> > >
> > > Just to inform you that now that the NAS driver is in GDAL trunk, I've
> > > been able to port its enhancements to the main GML driver. On the few
> > > samples I've tested, OS Mastermap GML files seem to be read correctly
> > > now.
> > >
> > > See http://trac.osgeo.org/gdal/ticket/3680
> > >
> > > Le Friday 02 July 2010 09:04:38 Martin Daly, vous avez écrit :
> > > > >     Here it is not only GDAL/OGR that has a problem!  Currently, I
> > > > > know of no importer that can handle this construct, other than the
> > > > > tool (from Snowflake) used by OSGB to generate it - and there is
> also
> > > > > the question of onwards storage.
> > > >
> > > > Not even close, I'm afraid.
> > > >
> > > > There are plenty of tools to read (all parts of) OS MM:
> > > >
> > > >
> http://www.ordnancesurvey.co.uk/oswebsite/products/osmastermap/informat
> > > >io n/ technical/software.html
> > > >
> > > > e.g. (an excellent one, at a very reasonable price...)
> > > >
> > > >
> http://www.ordnancesurvey.co.uk/oswebsite/products/osmastermap/informat
> > > >io n/ technical/software/cadcorp.html
> > > >
> > > > Also, as far as I am aware, OS GB use in-house software to generate
> the
> > > > data.
> > > >
> > > > Martin
>
>
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-- 
Best regards,
Chaitanya kumar CH.
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