specify projection

Hdf-forum archives
1

I have data in a simple projection: cylindrical equidistant.
I would like to write something into the hdf file to specify the projection.
Any idea what to specify?
Any examples?
Thanks

···

--
G. Garrett Campbell
NSIDC
303 492 5194

2

If you can use HDF-EOS, you can check
http://newsroom.gsfc.nasa.gov/sdptoolkit/userguide.html
HDF-EOS Library User's Guide Volume 1: Overview and
Examples<http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS_UG.pdf>for
HDF-EOS2
HDF-EOS Interface Based on HDF5, Volume 1: Overview and
Examples<http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS5_UG.pdf>for
HDF-EOS5

HDF-EOS can assure the geographic projection is specified without providing
lat/lon values.

If you prefer to use HDF5 or netCDF-4, you definitely need to provide
latitude and longitude values,
An attribute called units="degrees_east" for longitude and
units="degrees_north" for latitude should be specified to assure the CF
compliant.

check http://www.hdfgroup.org/HDF5/faq/cfattributes.html
You may find HDF5, netCDF4 and HDF-EOS5 examples that may be similar to
what you want to achieve.

Some HDF5 examples can also be found under
http://www.hdfgroup.org/ftp/HDF5/examples/

Kent

···

On Sun, May 12, 2013 at 11:30 PM, Garrett Campbell < garrett.campbell@nsidc.org> wrote:

I have data in a simple projection: cylindrical equidistant.
I would like to write something into the hdf file to specify the
projection.
Any idea what to specify?
Any examples?
Thanks

--
G. Garrett Campbell
NSIDC
303 492 5194

______________________________**_________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/**mailman/listinfo/hdf-forum_**hdfgroup.org<http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org>

--
Kent Yang The HDF Group
1800 So. Oak St., Suite 203, Champaign, IL 61820
217.531.6107
http://hdfgroup.org http://hdfeos.org

3

Thanks,
I have used lat/lon for satellite images where the data is not on a regular grid.
I was trying to save file size by not dumping out all the lat/lon float values.
I'll look at the examples.
Garrett Campbell

···

On 5/12/2013 9:51 PM, Kent Yang wrote:

If you can use HDF-EOS, you can check http://newsroom.gsfc.nasa.gov/sdptoolkit/userguide.html
HDF-EOS Library User's Guide Volume 1: Overview and Examples <http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS_UG.pdf> for HDF-EOS2
HDF-EOS Interface Based on HDF5, Volume 1: Overview and Examples <http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS5_UG.pdf> for HDF-EOS5

HDF-EOS can assure the geographic projection is specified without providing lat/lon values.

If you prefer to use HDF5 or netCDF-4, you definitely need to provide latitude and longitude values,
An attribute called units="degrees_east" for longitude and units="degrees_north" for latitude should be specified to assure the CF compliant.

check http://www.hdfgroup.org/HDF5/faq/cfattributes.html
You may find HDF5, netCDF4 and HDF-EOS5 examples that may be similar to what you want to achieve.

Some HDF5 examples can also be found under http://www.hdfgroup.org/ftp/HDF5/examples/

Kent

On Sun, May 12, 2013 at 11:30 PM, Garrett Campbell > <garrett.campbell@nsidc.org <mailto:garrett.campbell@nsidc.org>> wrote:

    I have data in a simple projection: cylindrical equidistant.
    I would like to write something into the hdf file to specify the
    projection.
    Any idea what to specify?
    Any examples?
    Thanks

    -- G. Garrett Campbell
    NSIDC
    303 492 5194 <tel:303%20492%205194>

    _______________________________________________
    Hdf-forum is for HDF software users discussion.
    Hdf-forum@hdfgroup.org <mailto:Hdf-forum@hdfgroup.org>
    http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

--
Kent Yang The HDF Group
1800 So. Oak St., Suite 203, Champaign, IL 61820
217.531.6107
http://hdfgroup.org http://hdfeos.org

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

--
G. Garrett Campbell
NSIDC
303 492 5194

4

If you want to save file size, then HDF-EOS Grid may be a way to go. If you
choose to use HDF5, don't forget to use compression.

Kent

···

On Mon, May 13, 2013 at 12:06 PM, Garrett Campbell < garrett.campbell@nsidc.org> wrote:

Thanks,
I have used lat/lon for satellite images where the data is not on a
regular grid.
I was trying to save file size by not dumping out all the lat/lon float
values.
I'll look at the examples.
Garrett Campbell

On 5/12/2013 9:51 PM, Kent Yang wrote:

If you can use HDF-EOS, you can check
http://newsroom.gsfc.nasa.gov/sdptoolkit/userguide.html
HDF-EOS Library User's Guide Volume 1: Overview and Examples<http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS_UG.pdf>for HDF-EOS2
HDF-EOS Interface Based on HDF5, Volume 1: Overview and Examples<http://newsroom.gsfc.nasa.gov/sdptoolkit/docs/HDF-EOS5_UG.pdf>for HDF-EOS5

HDF-EOS can assure the geographic projection is specified without
providing lat/lon values.

If you prefer to use HDF5 or netCDF-4, you definitely need to provide
latitude and longitude values,
An attribute called units="degrees_east" for longitude and
units="degrees_north" for latitude should be specified to assure the CF
compliant.

check http://www.hdfgroup.org/HDF5/faq/cfattributes.html
You may find HDF5, netCDF4 and HDF-EOS5 examples that may be similar to
what you want to achieve.

Some HDF5 examples can also be found under
http://www.hdfgroup.org/ftp/HDF5/examples/

Kent

On Sun, May 12, 2013 at 11:30 PM, Garrett Campbell < > garrett.campbell@nsidc.org> wrote:

I have data in a simple projection: cylindrical equidistant.
I would like to write something into the hdf file to specify the
projection.
Any idea what to specify?
Any examples?
Thanks

--
G. Garrett Campbell
NSIDC
303 492 5194

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

--
Kent Yang The HDF Group
1800 So. Oak St., Suite 203, Champaign, IL 61820
217.531.6107
http://hdfgroup.org http://hdfeos.org

_______________________________________________
Hdf-forum is for HDF software users discussion.Hdf-forum@hdfgroup.orghttp://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

--
G. Garrett Campbell
NSIDC303 492 5194

_______________________________________________
Hdf-forum is for HDF software users discussion.
Hdf-forum@hdfgroup.org
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

--
Kent Yang The HDF Group
1800 So. Oak St., Suite 203, Champaign, IL 61820
217.531.6107
http://hdfgroup.org http://hdfeos.org