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The HDF-EOS to GeoTIFF Conversion Tool (HEG) converts
HDF-EOS2
objects into
a
GeoTIFF
file. Unlike what the name of the tool implies, the output of the converted file is not limited to
the GeoTIFF format; it can be
in HDF-EOS2 format or binary format. This tool supports subsetting, reprojecting and resampling.
It does not open
HDF-EOS5
files.
This tool has a dedicated website
HEG.
that provides binaries, documents, news and so on.
From the HEG website, users can download precompiled binaries for Windows, Linux, Sun, Mac and SGI.
A detailed explanation for installing and using HEG can be found in the
HDF-EOS to GeoTIFF Conversion Tool(HEG) Stand-alone User's Guide.
HEG provides a graphic user interface. When opening an HDF-EOS2 file, HEG shows a list of
data fields within a grid or a swath.
HEG also retrieves metadata information about the grid or the swath and shows it under the Object Info section.
Figure 1 shows an example that used HEG to convert an HDF-EOS2 file. (For this example,
we used one
AMSR-E AE_RnGd file from NSIDC.
Download the file used in this example
here.)
Users can select one or multiple data fields. If multiple data fields are selected, the generated GeoTIFF file will have multiple bands. Users then choose the projection method for the converted GeoTIFF files and issue the conversion command.
As mentioned earlier, this tool can be used to generate not only GeoTIFF files but also HDF-EOS2 files or binary files. Several projection methods, such as the geographic projection and the polar stereographic projection, can be chosen for the generated files. Then, users can accept the conversion and start the conversion by clicking the 'Run' button.
The following sections briefly demostrate two more use cases for HEG.
Users can read HEG's
User's Guide
for details.
Since HEG can perform resampling, the projection method of the resulting GeoTIFF file can be
different than the projection method of the given HDF-EOS2 file. For example, one can choose
the geographic projection for the GeoTIFF file even though the source grid uses the North-polar
stereographic projection. (For the following example, we used one AMSR-E AE_SI12 file from NSIDC.
Download this file
here.)
One can choose resampling method among three options as
Figure 2 shows.
Even for swath data fields, one can choose various projection methods to generate GeoTIFF files. Since HEG can generate HDF-EOS2 files as well as GeoTIFF files, HEG can be used to convert a swath data field into a grid data field. One limitation is that users can choose only one resampling method,"Nearest Neighbor".
After HEG generates GeoTIFF files, one may want to verify the result using visualization tools.
Many GeoTIFF visualization tools are available. We provide a brief explanation on how to use
Global Mapper to display a GeoTIFF file
here.
