[FWTools] gdal_translate, -a_srs, -a_ullr, and Projections with Rotations

[Roger André]

Are the images in a standard UTM projection?  If so, you should be
able to create a worldfile for each of the images, and then use gdal
to assign the correct projection.  The worldfile would let you specify
rotation.
--

On Wed, Jul 22, 2009 at 10:59 AM, Peter Willis<pwillis at aslenv.com> wrote:
> Hello,
>
> Well, I tried with GCPs but no UTM geography is applied to
> the output unless I supply the '-a_ullr' option. Using
> -a_ullr causes the GCPs to be ignored and the same pixel
> size calculation errors occur due to the rotation and
> the actual bottom right coordinates with respect to the
> upper left.
>
> gdal_translate appears to be calculating the pixel size
> based on the UL and LR corners, which is normal. However,
> with GCPs there should be more of a rotation/translation
> applied to the geography.
>
> Perhaps an option to override the pixel size calculations
> in each dimension should be added to the utility...
>
> Peter
>
>
> Peter Willis wrote:
>> Hello,
>>
>> I just noticed the '-gcp' option for gdal_translate.
>> It occurs to me that this should provide the required projection
>> adjustments.
>>
>> Peter
>>
>>
>> Peter Willis wrote:
>>> Hello,
>>>
>>> I am applying geography to some UTM based images.
>>> The images have a 1.9 degree rotation.
>>>
>>> Is there a way to assign a rotation to the projection
>>> using gdal_translate?
>>>
>>> If not, is there a way to assign the rotation using
>>> any other GDAL tools?
>>>
>>> Thanks
>>>
>>> Peter
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>>>
>>>
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