[gdal-dev] Can't read transformation coefficients from tiff

[Chaitanya kumar CH]

Chris,

GDAL is using the GCPs for location information.

On Thu, Apr 7, 2011 at 4:08 PM, Goo Creations <goocreations at gmail.com>wrote:

> Yes, here it is:
>
>
>
> Size is 8415, 1368
> Coordinate System is `'
> GCP Projection =
> GEOGCS["WGS 84",
>     DATUM["WGS_1984",
>         SPHEROID["WGS 84",6378137,298.257223563,
>             AUTHORITY["EPSG","7030"]],
>         AUTHORITY["EPSG","6326"]],
>     PRIMEM["Greenwich",0],
>     UNIT["degree",0.0174532925199433],
>     AUTHORITY["EPSG","4326"]]
> GCP[  0]: Id=1, Info=
>           (1,1) -> (1.09027789320281,36.5294598527946,0)
> GCP[  1]: Id=2, Info=
>           (8415,1) -> (1.69376245781042,36.497946615707,0)
> GCP[  2]: Id=3, Info=
>           (8415,1368) -> (1.68268551099186,36.5851791048298,0)
> GCP[  3]: Id=4, Info=
>           (1,1368) -> (1.06532262333098,36.6082043228718,0)
> Metadata:
>   TIFFTAG_DATETIME=2010:10:05 06:46:58
>   AREA_OR_POINT=Point
> Image Structure Metadata:
>   INTERLEAVE=BAND
> Corner Coordinates:
> Upper Left  (    0.0,    0.0)
> Lower Left  (    0.0, 1368.0)
> Upper Right ( 8415.0,    0.0)
> Lower Right ( 8415.0, 1368.0)
> Center      ( 4207.5,  684.0)
> Band 1 Block=8415x128 Type=UInt16, ColorInterp=Gray
>
>
>
>
>
>
>
>
> On Thu, Apr 7, 2011 at 11:51 AM, Chaitanya kumar CH <chaitanya.ch@
> gmail.com> wrote:
>
>> Chris,
>>
>> Can you provide the gdalinfo output of the geotiff?
>>
>>
>> On Thu, Apr 7, 2011 at 2:29 PM, Goo Creations <goocreations at gmail.com>wrote:
>>
>>> I've worked through some QGis code and noticed that if this happens,
>>> GDALAutoCreateWarpedVRT is called on the image to create a copy. So
>>> GDALAutoCreateWarpedVRT somehow retrieves some sort of metadata to
>>> accomplish this.
>>>
>>>
>>>
>>>
>>> On Thu, Apr 7, 2011 at 10:44 AM, Goo Creations <goocreations at gmail.com>wrote:
>>>
>>>> A couple of different apps, such as QGis and Monteverdi (who rotated the
>>>> image). If I view the image in a normal image viewer (or application not
>>>> built on top of GDAL, the image is not rotated). Hence there must be some
>>>> metadata from GDAL these applications use to rotate the image.
>>>>
>>>> And yes, I can read other metadata.
>>>>
>>>> Chris
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, Apr 7, 2011 at 10:34 AM, Chaitanya kumar CH <chaitanya.ch@
>>>> gmail.com> wrote:
>>>>
>>>>> Chris,
>>>>>
>>>>> What did you use to view the image? Were you able to read any other Geo
>>>>> related data with that?
>>>>>
>>>>> On Thu, Apr 7, 2011 at 1:56 PM, Goo Creations <goocreations at gmail.com>wrote:
>>>>>
>>>>>> Hi all
>>>>>>
>>>>>> I tried to read the transformation coefficients by using
>>>>>> GDALDataset::GetGeoTransform. This function however returned CE_Failure, so
>>>>>> i assume that the values are not stored in the metadat.
>>>>>> When I view the image, the image is rotated. There is no world file or
>>>>>> anything that could cause the rotation.
>>>>>>
>>>>>> So my question: If these values are not stored in the metadata, how
>>>>>> does GDAL handle the rotation, pixel size, etc?
>>>>>>
>>>>>> Chris
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> gdal-dev mailing list
>>>>>> gdal-dev at lists.osgeo.org
>>>>>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Best regards,
>>>>> Chaitanya kumar CH.
>>>>> /tʃaɪθənjə/ /kʊmɑr/
>>>>> +91-9494447584
>>>>> 17.2416N 80.1426E
>>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> Best regards,
>> Chaitanya kumar CH.
>> /tʃaɪθənjə/ /kʊmɑr/
>> +91-9494447584
>> 17.2416N 80.1426E
>>
>
>


-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
17.2416N 80.1426E
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