[Gdal-dev] Projection-Problem

[Stephan Holl]

Hello Frank,

thanks for looking into this.

On Wed, 10 May 2006 11:14:40 -0400 Frank Warmerdam
<warmerdam at pobox.com> wrote:

> Stephan Holl wrote:
> > PROJCS["GK Zone 4 (DHDN)",
> >     GEOGCS[,
> >         DATUM[,
> >             SPHEROID["Bessel
> > 1841",6377397.155,299.1528128],582.000000,105.000000,414.000000,-1.040000,-0.350000,3.080000,8.300000],
> > PRIMEM["Greenwich",0.000000], UNIT["Decimal
> > Degree",0.01745329251994330]], PROJECTION["Transverse Mercator"],
> >     PARAMETER["Scale_Factor",1.000000],
> >     PARAMETER["Central_Meridian",12.000000],
> >     PARAMETER["False_Easting",4500000.000000],
> >     UNIT["Meter",1.000000000000],
> >     AUTHORITY["Oracle","82032"]]
> 
> Stephan,
> 
> Whew, this is a screwy WKT definition.  Is that really what is stored
> in Oracle's WKTEXT field of the MDSYS.CS_SRS table?  What does it look
> like there?

I have attached a (sadly formated) MDSYS.CS_SRS-table extract.

> The extra unlabelled numbers in the DATUM are presumably TOWGS84
> parameters, but improperly labelled.  I haven't noticed this before.
> 

[...]

> > Here you can see that the Datum now contains "Mean_Sea_Level".
When
> > inspecting the written .prj-file from the shape I cannot find any
> > entry in the datum-parameters like "Mean_Sea_Level".
> 
> I have no idea where ogr2ogr would be getting Mean_Sea_Level from.
> Hmm, looking in gdal_datum.csv it is the "zeroth" record.  Perhaps it
> is getting picked up from there as some sort of default.

Yes, I have found this as well in this file, but could not find the
code where this "default" was set.

> 
> If you can provide me the extract WKTEXT from the MDSYS.CS_SYS table
> I'll see if I can improve the handling.

Please find this attached.

Thanks for looking into this again.

Best regards

	Stephan


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-------------- next part --------------
SQL> SELECT * FROM MDSYS.CS_SRS WHERE AUTH_SRID = 82032;

CS_NAME                                                                    SRID
-------------------------------------------------------------------- ----------
 AUTH_SRID
----------
AUTH_NAME
--------------------------------------------------------------------------------
WKTEXT
--------------------------------------------------------------------------------
CS_BOUNDS(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z), SDO_ELEM_INFO, SDO_ORDINATES)
--------------------------------------------------------------------------------
GK Zone 4 (DHDN)                                                          82032
     82032
Oracle

PROJCS["GK Zone 4 (DHDN)", GEOGCS [ "", DATUM ["", SPHEROID ["Bessel 1841", 6377
397.155, 299.1528128], 582.000000, 105.000000, 414.000000, -1.040000, -0.350000,
 3.080000, 8.300000 ], PRIMEM [ "Greenwich", 0.000000 ], UNIT ["Decimal Degree",
 0.01745329251994330]], PROJECTION ["Transverse Mercator"], PARAMETER ["Scale_Fa
ctor", 1.000000], PARAMETER ["Central_Meridian", 12.000000], PARAMETER ["False_E
asting", 4500000.000000], UNIT ["Meter", 1.000000000000]]

SQL>