[gdal-dev] What is the format of a .prf file?

[Rainer M Krug]

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On 21/03/13 14:48, Stephen Woodbridge wrote:
> On 3/21/2013 4:08 AM, Rainer M Krug wrote: On 20/03/13 16:44, Andre Joost wrote:
>>>> Am 20.03.2013 16:01, schrieb Rainer M Krug:
>>>> 
>>>>> What I don't like is that I have to specify t_srs in such a long way. It states that
>>>>> t_srs can be "a .prf file containing well known text", but I can't figure out what a
>>>>> .pdf file is. Would for exmple work, if I put
>>>>> 
>>>>> +proj=aea +lat_1=-28.25 +lat_2=-29.75 +lat_0=-29 +lon_0=30.75 +x_0=0 +y_0=0
>>>>> +datum=WGS84 +units=m +no_defs
>>>>> 
>>>>> in t.prf and refer to it in gdalward as "-t_sts t.prf"?
>>>>> 
>>>> 
>>>> No, the proj definition text is not "well known text" WKT.
>>>> 
>>>> 
>>>>> Are there any examples available for prf files and allowed formats?
>>>> 
>>>> It's simply the same format as in every shapefiles .prj file.
>>>> 
>>>> For example ogr2ogr -s_srs epsg:3375 -t_srs epsg:4245 Malay-Kertau.shp rivers-neu.shp
>>>> ogr2ogr -s_srs epsg:3375 -t_srs Malay-Kertau.prj Malay-prj.shp rivers-neu.shp
>>>> 
>>>> returns two identical outputs, where Malay-Kertau.prj contains the definition used in the
>>>> first run with EPSG:4245.
> 
> Thanks for the response.
> 
> So the file Malay-Kertau.prj would then contain the text:
> 
> epsg:4245
> 
> ?
> 
>> No you would need something like:
> 
>> GEOGCS["GCS_Kertau",DATUM["D_Kertau",SPHEROID["Everest_1830_Modified",6377304.063,300.8017]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]
>
>> 
> 
>> I found this here: 
>> http://webhelp.esri.com/arcims/9.3/general/mergedprojects/ArcXMLGuide/elements/gcs.htm
> 
>> webhelp.esri.com/arcims/9.3/general/mergedprojects/wms_connect/wms_admin/srs_list.htm
> 
>> WKT for projections refers to ESRI projection info NOT proj4 epsg codes.

Ah - now I understand it. "Well-known text" *is* a format of specifying
projections. I thought it was referring to "ascii text file" or something
along these lines. Maybe a link to a WKT format specification would be
useful or at least changing the text

"name of a .prf file containing well known text"
 to
"name of a .txt file containing the projection in WKT (well known text) format"

as pdr file irritated me as well...

Cheers,

Rainer
> 
>> Read this:
> 
>> http://www.nceas.ucsb.edu/scicomp/recipes/projections
> 
>> -Steve W
> 
> 
> 
> So I have to put into the file simply the text as supplied to -t_srs ?
> 
> And what is the difference between a .prj file used by shape files and a .pdf file (format
> wise)?
> 
> Rainer
> 
> 
> Rainer
> 
>>>> 
>>>> Greetings, André Joost
>>>> 
>>>> 
>>>> 
>>>> _______________________________________________ gdal-dev mailing list
>>>> gdal-dev at lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
> 
> 
>> _______________________________________________ gdal-dev mailing list 
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>> 
> 
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- -- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys.
(Germany)

Centre of Excellence for Invasion Biology
Stellenbosch University
South Africa

Tel :       +33 - (0)9 53 10 27 44
Cell:       +33 - (0)6 85 62 59 98
Fax :       +33 - (0)9 58 10 27 44

Fax (D):    +49 - (0)3 21 21 25 22 44

email:      Rainer at krugs.de

Skype:      RMkrug
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