[gdal-dev] OGR - S57 - geometry extraction issue

[Even Rouault]

David,

As far as I can see from s57objectclasses.csv, POSACC and QUAPOS are not 
attributes of the COALNE class, but only from the M_ACCY (Accuracy of data) 
and M_QUAL (Quality of data) for POSACC, and M_SREL (Survey reliability) for 
QUAPOS.

You might probably retrieve those attributes by identifying features of COALNE 
and M_ACCY/M_QUAL/M_SREL that share the same geometry primitives with the 
NAME_RCNM and NAME_RCID attributes added with RETURN_LINKAGES=ON. Or perhaps 
an easier way would be by layer algebra computation to find which features of 
COALNE are inside features of M_ACCY/M_QUAL/M_SREL. Probably with the Identify 
method.

See 
http://download.osgeo.org/gdal/workshop/foss4ge2015/workshop_gdal.html#__RefHeading__6015_1333016408

By the way, when testing, I identified a regression in 2.1.1 where the open 
options of the S57 driver were ignored, that I just fixed per : 
https://trac.osgeo.org/gdal/ticket/6609

Even

> Hello all,
> 
> We are trying to render S57 files as ENC through Geoserver.
> 
> We convert S57 to shapefiles thanks to ogr2ogr : 1 shapefile for 1 class
> (ex : COALNE) and 1 geometry type (LINE) :
> ogrinfo -oo "RETURN_PRIMITIVES=ON" -oo "RETURN_LINKAGES=ON" -oo
> "LNAM_REFS=ON" CELLLL.000 COALNE
> ogr2ogr -skipfailures  -where "OGR_GEOMETRY='POINT' or
> OGR_GEOMETRY='MULTIPOINT'" SOUNDG_points.shp CELLLL.000 SOUNDG
> 
> We use gdal-2.1.0 with the S57_CSV environnement variable
> (S57_CSV=/usr/local/share/gdal/ with s57*.csv files).
> 
> 
> We noticed that objects (of COALNE class for example) have multiple
> geometries and each sub-geometry have attributes like POSACC and QUAPOS
> which are important for S52 representation.
> We've succeeded to extract primitives (Edge, isolated points, connected
> points, ...), but it looks very complex to operate.
> 
> 
> We have some problems to extract geometries from s57 objects :
> - we noticed that, for an object, all sub-geometries are aggregated to one
> geometry
> - we didn't succeed to extract geometry attributes like POSACC and QUAPOS
> 
> 
> 1) Is there a way to not aggregate sub-geometries of an object and get this
> list of sub-geometries ?
> 2) Is there a way to extract geometry attributes like POSACC and QUAPOS ?
> 3) If not, are these features planned ?
> 
> 
> Thanks for your help !
> 
> 
> David

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