[Gdal-dev] ASTER HDF Metadata problem

[Andrey Kiselev]

On Thu, Jan 29, 2004 at 10:34:06AM +0100, Fr?d?ric Trastour wrote:
> you will find attached the contents of structmetadata.0 and
> structmetadata.1.

Well, looks like you are right and these files should be concatenated.

> I am working on hdf4dataset.cpp. My plans are to provide access to all
> metadata using GetMetadata and specific "Domain" values. For example,
> GetMetadata("Structmetadata") returns the ODL content of the
> concatened  Structmetadata.0 and Structmetadata.1
> Do you think that it is the right approch ?

Hmm, it may be good for Structmetadata, but driver parsing abilities
very poor now. I'm working on improving the driver using original
HDF-EOS code and thing will be changed in the next version of the driver
(but I want to commit new driver only after the next GDAL release. The
current one is more or less tested and works for many cases). Anyway,
what data you want to extract from the Structmetadata record?

> In addition, I need in my application to read other data stocked in
> the HDF File like the Ancillary_Data. I don't know if it's the hdf
> driver should provide access to this data using the metadata mecanism
> or another one ? Perhaps the driver should implement
> 'GetInternalHandle' allowing the application to access the HDF file
> directly ?

I'm not sure that GDAL is a good choice to work with HDF so intimately.
We are limited by the data model, which is designed to handle images and
simple record collections (metadata). HDF files contain tables of
different types and multidimension arrays, but we can work with arrays
only, because they can be interpreted as images.

Generally it is possible to add new base data structure GDALTable which
can be used in the driver.

I'm CC:ing to the mailing list, probably Frank can add something on this
topic.

						Andrey

-- 
Andrey V. Kiselev
Home phone:  +7 812 5274898  ICQ# 26871517