[gdal-dev] Multiresolution images

Lowell Johnson ldjohn at u...
Tue Sep 25 12:03:58 EDT 2001

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

> 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

> 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.


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

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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