[postgis-users] "Deutsches Hauptdreiecksnetz" missing in spatial_ref_sys

[Guido Lemoine]

Frank,

It's just that EPSG:31469 is the equivalent of the PRJ file output you 
presented.
I guess you're looking at some very high resolution (LIDAR?) data. Would be
interesting to know how they georeferenced that data to understand possible
problems in (systematic) shifts. Frank Warmerdam (the guy behind GDAL)
has suggested that (re)projections are generally precise within a few 
meters, if
you use EPSG parameters (you'll notice a difference in precision already 
between
the SRTEXT output and your PRJ parameters).

GL

Frank Durstewitz wrote:
> Thanks Guido,
>
> i found this record (and others which look similar), but it's not the 
> same and i need the exact definition.
>
> The data i have to examine is claimed to be the exactest data 
> available for building positions in germany (top roof), and i have to 
> verify this very careful, because the whole dataset is very expensive.
>
> Anyone other ideas?
>
> TIA, Frank
>
>
> Guido Lemoine am 29.07.2008 08:56:
>> Frank,
>>
>> Look at EPSG=31469
>>
>> "PROJCS["DHDN / Gauss-Kruger zone 
>> 5",GEOGCS["DHDN",DATUM["Deutsches_Hauptdreiecksnetz",SPHEROID["Bessel 
>> 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],AUTHORITY["EPSG","6314"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4314"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",15],PARAMETER["scale_factor",1],PARAMETER["false_easting",5500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AUTHORITY["EPSG","31469"]]" 
>>
>>
>> GL
>>
>> Frank Durstewitz wrote:
>>> Hi together,
>>>
>>> please, can someone convert the prj definition below into a insert 
>>> statement for use in spatial_ref_sys?
>>>
>>> I got some data for evaluation, but since the datum is not in my 
>>> spatial_ref_sys, i'm stuck. And i'm not sure how to create the 
>>> necessary sql.
>>>
>>> PROJCS["Transverse_Mercator",GEOGCS["Geographic Coordinate 
>>> System",DATUM["D_DEUTSCHES_HAUPTDREIECKSNETZ",SPHEROID["Bessel 
>>> 1841",6377397.155,299.1528131060786]], 
>>> PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433]], 
>>> PROJECTION["Transverse_Mercator"],PARAMETER["scale_factor",1], 
>>> PARAMETER["central_meridian",12],PARAMETER["latitude_of_origin",0], 
>>> PARAMETER["false_easting",4500000], 
>>> PARAMETER["false_northing",0],UNIT["Meter",1]]
>>>
>>> TIA, Frank
>>>
>>> ------------------------------------------------------------------------ 
>>>
>>>
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>>> postgis-users at postgis.refractions.net
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>>>   
>>
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-- 
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Guido Lemoine
Joint Research Centre, European Commission
Institute for the Protection and Security of the Citizen (IPSC)
Support to External Security
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