[gdal-dev] Re: The world is flipped redux

[Jamie Adams]

It looks like Matt's script doesn't modify the geotransform, just reverses
the rows in the image.  You probably need to calculate a new ulx and make
sure the pixel dimensions are expressed correctly (+/-).

>From the sound of it, your original image would actually be right if the
viewer software read the corner coordinates and displayed the image based on
those.  :-)

-Jamie

On Fri, Aug 8, 2008 at 4:51 PM, Roger André <randre at gmail.com> wrote:

> My apologies to Matt, the flip_raster.py does flip something, as when I
> compare the images in OpenEV, I can see that they are reversed.  But when I
> compare their corner coords with gdalinfo, they appear identical.
>
> $ gdalinfo test.tif
> <snip>
> Corner Coordinates:
> Upper Left  ( -71.3600000, -23.5000000)
> Lower Left  ( -71.3600000,  -8.5000000)
> Upper Right ( -55.7000000, -23.5000000)
> Lower Right ( -55.7000000,  -8.5000000)
>
> $ gdalinfo bolivia_fullres.tif
> <snip>
> Corner Coordinates:
> Upper Left  ( -71.3600000, -23.5000000)
> Lower Left  ( -71.3600000,  -8.5000000)
> Upper Right ( -55.7000000, -23.5000000)
> Lower Right ( -55.7000000,  -8.5000000)
>
> My head hurts.
> --
>
>
> On Fri, Aug 8, 2008 at 4:24 PM, Roger André <randre at gmail.com> wrote:
>
>> Ok, this is driving me nuts, I can't handle "South is up" anymore.  I have
>> NetCDF derived GMT grids which have a flipped y-axis.  This makes for
>> georeferencing that looks like this:
>> Corner Coordinates:
>> Upper Left  ( -90.0000000, -90.0000000)
>> Lower Left  ( -90.0000000,   0.0000000)
>> Upper Right (   0.0000000, -90.0000000)
>> Lower Right (   0.0000000,   0.0000000)
>>
>> I've seen some old discussions about this, but haven't really found a good
>> solution.  I've tried a "flip_raster.py" utility that Matt Perry wrote, but
>> it doesn't seem to do anything with my data.  (probably due to my crappy
>> data, not Matt's tool) I've also read that there have been some rewrites of
>> the NetCDF driver that are supposed to be able to deal with this, but I'm
>> not sure about that.
>>
>> How have others out there dealt with this issue?  I'd like to be able to
>> convert the grids into GeoTIFF's and have the TIFF's be "right" side up.
>>
>> Thanks,
>>
>> Flipped-off Roger
>> --
>>
>
>
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