[gdal-dev] OGR - S57 - geometry extraction issue
s duclos
sylvain_duclos at yahoo.com
Sat Mar 4 08:00:49 PST 2017
David,
>Moreover, I was confronted with the TEMP_BUFFER_SIZE of ogrfeature when converting IntegerList to String because some >objects have many subgeometries and the result is truncated (finishing by '...)') and not exploitable. The limit is 80 >characters, I tried to increase to 254 (max string length in shp) but it's not enough in some cases : for now, I just log >the complete Integerlist in stderr and I handle all errors... I tried the splitlistfield option but it's not very easy to >exploit...
Conserning TEMP_BUFFER_SIZE my hack is to realloc() when more room is needed.
But OGR is about WKT/WKB. Here we are talking internal representation. So when I
need this info I just patch OGR.
Attached is my patch (ogrfeature.cpp.diff) to give you an idea.
rgds,
Sylvain.
On Saturday, March 4, 2017 10:12 AM, David FERDOILLE <david.ferdoille at gmail.com> wrote:
Hi,
I'm sorry, I didn't have any time to work on integrating s57 data to geoserver through ogr during several months but I got time to work on it last month.
The main issue : objects may be composed of multiple primitives (isolated node or edge) with geometric attributes like posacc or quapos but ogr makes a aggregation of geometries and ignore those geometric attributes.
We succeed to manage this issue by this process :
1) extract all classes to shapefile with all relations between objects and primitives
ogr2ogr
-oo "RETURN_PRIMITIVES=ON"
-oo "RETURN_LINKAGES=ON"
-oo "LNAM_REFS=ON"
-nlt "MULTILINESTRING"
-where "OGR_GEOMETRY='LINESTRING' or OGR_GEOMETRY='MULTILINESTRING'"
-fieldTypeToString IntegerList
cell-class-line.shp
cell.000
class
2) extract all primitives to shapefile with a s57-reader modification which return posacc and quapos values
ogr2ogr
-oo "RETURN_PRIMITIVES=ON"
-oo "RETURN_LINKAGES=ON"
-oo "LNAM_REFS=ON"
-nlt "MULTIPOINT"
-skipfailures
cell-isolatednode-point.shp
cell.000
IsolatedNode
To get posacc and quapos attributes, the S57Reader::ReadVector function was modified, can I propose the modification to the community on github ?
3) integrate all shapefiles in a PostgreSQL/PostGIS database and work on it to construct all objects-subgeometries with 'name_rcnm' and 'name_rcid' to obtain a database compatible with geoserver.
During my tests, I found some differences between s57attributes.csv, s57objectclasses.csv and the s57 reference (on www.s-57.com for example), I will propose the update on github.
Moreover, I was confronted with the TEMP_BUFFER_SIZE of ogrfeature when converting IntegerList to String because some objects have many subgeometries and the result is truncated (finishing by '...)') and not exploitable. The limit is 80 characters, I tried to increase to 254 (max string length in shp) but it's not enough in some cases : for now, I just log the complete Integerlist in stderr and I handle all errors... I tried the splitlistfield option but it's not very easy to exploit...
Regards
David
Le 07/12/2016 à 22:00, Mike a écrit :
David, did you ever figure this one out? I've run into the same situation, where I need the spatial attributes.
>
>
>-Mike
>
>
>On Aug 12, 2016 1:32 AM, "David Ferdoille" <david.ferdoille at gmail.com> wrote:
>
>Hello,
>>
>>
>>Thanks for the responses,
>>
>>After a long afternoon of tests :
>>I try to access a WRECKS object, compose by an only point, with a QUAPOS specific value of 5, and an POSACC of 500.0 (find it using CARIS Easy View)
>>
>>1-
>>In ogrinfo -oo "RETURN_PRIMITIVES=ON" -oo "RETURN_LINKAGES=ON" -oo "LNAM_REFS=ON" file.000 WRECKS, I found the object, but no QUAPOS or POSACC (logical because the 2 attributes are not directly linked to the object, but to the geometry).
>>
>>2-
>>In ogrinfo -oo "RETURN_PRIMITIVES=ON" -oo "RETURN_LINKAGES=ON" -oo "LNAM_REFS=ON" file.000 IsolatedNode, I found the node representing the object but also no QUAPOS or POSACC.
>>
>>3-
>>In ogrinfo -oo "RETURN_PRIMITIVES=ON" -oo "RETURN_LINKAGES=ON" -oo "LNAM_REFS=ON" file.000 M_QUAL, I found an only object, spatially containing my wreck object, but POSACC is null.
>>
>>4-
>>In ogrinfo -oo "RETURN_PRIMITIVES=ON" -oo "RETURN_LINKAGES=ON" -oo "LNAM_REFS=ON" file.000 M_QUAL, I found 20 objects, but QUAPOS is null for all of them.
>>
>>5-
>>No M_ACCY table is present in my dataset.
>>
>>
>>According to me, the good way to get these attributes, is the second one (2-), but even if I try a lot of things, I didn’t manage to :
>>- Trying all the S57 option with –oo
>>- Trying to change the CSV types and attributes catalog used by GDAL
>>- Etc…
>>
>>
>>Does someone know if it is possible to get these attribute through GDAL/OGR ?
>>If not, is there another way to get this attributes (python GDAL scripts ? another command line software ?)
>>
>>Thanks again for your help !
>>
>>
>>Regards
>>
>>
>>David
>>
>>
>>2016-07-29 11:31 GMT+02:00 teddy guerin <teddyguerin at yahoo.fr>:
>>
>>Hi,
>>>Up for my previous answer.
>>>
>>>I was wrong for lines and area values POSACC, QUAPOS are on edges and not on "real object".
>>>
>>>
>>>Regards
>>>Ted
>>>
>>>
>>>
>>>
>>>
>>>________________________________
>>> De : David Ferdoille <david.ferdoille at gmail.com>
>>>À : gdal-dev at lists.osgeo.org
>>>Envoyé le : Mercredi 27 juillet 2016 15h12
>>>Objet : [gdal-dev] OGR - S57 - geometry extraction issue
>>>
>>>
>>>
>>>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
>>>______________________________ _________________
>>>gdal-dev mailing list
>>>gdal-dev at lists.osgeo.org
>>>http://lists.osgeo.org/mailman /listinfo/gdal-dev
>>>
>>>
>>
>>
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