[gdal-dev] Multiresolution images

[Lowell Johnson]

On Tue, 25 Sep 2001, Frank Warmerdam wrote:
> Lowell Johnson wrote:
> 
> > Maybe I'm missing something, but it seems that it may be possible to
> > interpret a given image as multi-resolution if each GDALRasterBand object
> > has a different XSize, YSize.
> 
> 
> Lowell,
> 
> In theory that might be possible; however, GDAL was developed with the
> assumption that all bands on a given GDALDataset are of the same size and
> same geographic area. Any breaking of this assumption could have dramatic
> consequences.

We do expect every band to have the same corner coordinates (same geographic
size), but the pixel ground distance and data types may vary from band to
band.

> I would be excited to have your team utilize GDAL and I am willing to do
> what I can to make that more practical, including providing CVS commit access
> to your developers.

Thank you. That may be very convenient.

> Note that GDAL already has slightly indirect support for CIB via the link to
> OGDI. OGDI has a pretty good seamless CIB reader. I have been using that via
> GDAL for a recent military pilot project run by OGC.
> 
> Is modis data distributed in HDF-EOS format? I am very keen to build HDF-EOS
> support into GDAL and I am following a couple of contract possibilities to make
> that happen.

I haven't worked directly on this, so I'm only passing on what I've been
told. The MODIS data is "supposedly" in HDF-EOS format, but the developer
that wrote the reader says that you can't expect to ingest a MODIS image
with a standard HDF-EOS reader. The format has been tweaked in some
fashion.

> What landsat 7 format are you looking to implement? Is this the FAST-L7A
> format? I have had some interest in it before, but never got around to
> implementing it.

The primary Landsat 7 format is straight HDF. We have a separate ingest
routine for handling various Fast format datasets including Fast-L7A.

> NDF is the NLAPS data format, right? That should be easy to implement. I
> did it once in PCIs GeoGateway.

Yes, NLAPS.

Thanks for your response. As I implied earlier, we are still in the midst
of our investigations and have not reached a decision regarding our new
image I/O efforts, but your comments have fostered additional interest in
GDAL.


Lowell
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Lowell D. Johnson ldjohn at u...
Software Engineering
Raytheon Systems
EROS Data Center
47914 252nd Street, Mundt Federal Bldg
Sioux Falls, SD 57198
phone: (605)594-6872 fax: (605)594-6940
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