[postgis-users] suitable projection in metric system ?

[ahmet temiz]

thank you Emily & Francis.

Answers were very valuable indeed.

kind regards

05 Kasım 2010 02:16 tarihinde Francis Markham <fmarkham at gmail.com> yazdı:
> Hi Ahmet,
>
> My quick Googling hasn't come up with a widely used pre-defined projection
> for Turkey that is non zonal (either UTM or Gauss-Kruger), at least not in
> the EPSG database.  Apparently, MapInfo ships with a Turkish Lambert
> projection in its mapinfow.prj file, which is widely available on the web.
> I took the parameters from that projection and created an entry on
> spatialreference.org as SR-ORG:7006.  This can be inserted into PostGIS as a
> new SRS as:
>
> INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext)
> values ( 97006, 'sr-org', 7006, '', 'PROJCS["Turkish Lambert Conformal
> (K.Eren -
> ED50)",GEOGCS["GCS_European_1950",DATUM["D_European_1950",SPHEROID["International_1924",6378388.0,297.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",1003827.0],PARAMETER["False_Northing",-1183453.0],PARAMETER["Central_Meridian",36.0],PARAMETER["Standard_Parallel_1",37.5],PARAMETER["Standard_Parallel_2",40.5],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",25.0],UNIT["Meter",1.0]]');
>
> This can then be used as SRS number 97006.
>
> Note that this projection uses the ED50 datum.  If your coordinates are in
> WGS84 (the standard for GPS) or some other datum, it might be convenient to
> create a new SRS using the above parameters but based on another datum.
>
> Furthermore, If you are happy to keep your data in geographic coordinates
> (lat/lon) you may wish to investigate the Geography type as Emily
> suggested.  Be aware, however, that this has some cost in terms of speed for
> some operations, and not all operations defined in PostGIS for Geometry are
> currently available for Geography types.
>
> Good luck,
>
> Francis Markham
>
> 2010/11/5 ahmet temiz <ahmettemiz88 at gmail.com>
>>
>> hello
>>
>> I was wondering if you could tell me which projection in metric system
>> is  suitable for whole country (TURKEY) ?
>> I thought to use UTM, but it has three different zones.
>>
>> If you answer me, I will appreciate
>>
>> regards
>>
>>
>> --
>> Ahmet Temiz
>> Jeoloji Müh.
>> Planlama ve Zarar Azaltma Dairesi Başkanlığı
>> Bilgi ve CBS grubu
>> Eskişehir Yolu 10. km.
>> Lodumlu / Ankara
>> Tel : 0 312 2872680 / 1535
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>
>
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-- 
Ahmet Temiz
Jeoloji Müh.
Planlama ve Zarar Azaltma Dairesi Başkanlığı
Bilgi ve CBS grubu
Eskişehir Yolu 10. km.
Lodumlu / Ankara
Tel : 0 312 2872680 / 1535