[gdal-dev] sounding point handling by OGR library

Yilmaz Arslanoglu yilmaz.arslanoglu at gmail.com
Tue Sep 29 12:57:20 EDT 2009

Thank you very much Frank for the quick and clear answers.

Best wishes,

On Tue, Sep 29, 2009 at 6:20 PM, Frank Warmerdam <warmerdam at pobox.com> wrote:
> Yilmaz Arslanoglu wrote:
>> Hi;
>> I had some questions regarding the additional feature of sounding
>> point handling by the OGR library.
>> I know that we need to turn on the options SPLIT_MULTIPOINT and
>> ADD_SOUNDG_DEPTH options on.
>> 1) Is there a way to turn them individually on without affecting the
>> other suboptions in OGR_S57_OPTIONS ?
>>    Because if we do it by the following statement:
>>   CPLSetConfigOption("OGR_S57_OPTIONS",
>>   Then there is a possibility to overwrite the other suboptions
> Yilmaz,
> You are correct, calling CPLSetConfigOption() will clear the previous
> setting, so if you want things amalgamated you need to do it
> yourself in code in some fashion.
>> 2) With turning ADD_SOUNDG_DEPTH option on, the points become three
>> dimensional, where the Z
>>    member variable contains the retrieved depth value I guess. Here,
>> my question is, does this depth
>>    retrieval process take care of any unit conversions (meters,
>> fathoms, feet, etc.) ?
> I do not believe it is doing any unit conversion.  You will
> get a Z coordinate in the depth units that it appears in
> the depth attribute.
> In general OGR and OGRSpatialReference do not attempt to
> address the units of Z values even though there is an OGC
> coverage of compound (ie. 2D + elevation) coordinate systems.
> Best regards,
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent

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