recognizes the fact that there are multiple resolutions within the file and displays them in the
metadata window under Pixel Size. You can choose to output any combination of the available
datasets, but each will be placed in a separate file due to how they are processed by the tool.
Each output file will contain appropriate band number designations and wavelength values.
After clicking on Process, you will see two ENVI progress bars: one related to the conversion of
the current dataset and one related to the overall conversion process.
The tool also recognizes that Level 1A data does not contain georeferencing information
(indicated by the Native Projection being set to None in the metadata viewer). However, if you
have access to the related Geolocation product (MOD03/MYD03), you can use it to project the
Level 1A data. To do so, select Projected or Standard and Projected under Output Type and
then click on Input Geolocation File. You will be prompted to supply an appropriate file. A filter
is provided to aid you in finding the correct product and the current Level 1A filename will show
up in the title bar of the file selection dialog. In order to proceed, the second, third and fourth
sections of the Level 1A filename and geolocation filename have to match. For example, a
Level 1A file with the name “MYD01.A2006007.0300.005.2007078081622.hdf” requires a
geolocation file with the name “MYD03.A2006007.0300.005.2006125230829.hdf.” If the
supplied filenames do not match, the projection options section will be greyed out and you will
not be allowed to proceed with the conversion. If the filenames do match, the most appropriate
UTM zone for the supplied data is automatically calculated and made available (Figure 3).
Please note that for scenes in polar regions, Universal Polar Stereographic (UPS) will be
selected instead. Standard resampling methods (Nearest Neighbor, Bilinear, and Cubic
Convolution) are available. Bowtie correction is performed automatically. Output pixel size is
automatically determined based on product type and dataset. For projections that do not use
meters, the meter-based pixel size is automatically converted to one that is appropriate. You
also have the option of providing your own fill value to use during the conversion process and
your own background value to use during the projection process. The default value for both is 0.
If a value less than zero is provided, zero is used instead. Note: An alternative pixel size can
be provided through the programmatic interface.
Filenames for converted data
For Level 1A files, two types of filenames are possible. They are constructed as follows:
• Rootname + Dataset Name + Raw_DN.img (unprojected data)
• Rootname + Dataset Name + Raw_DN_georef.img (projected data)
A Note on Output Type
Because MCTK is a conversion utility, you will always receive at least one ENVI format file as
output. If you choose to output projected data using the Projected or Standard and Projected
option, two sets of output files will be generated. The first set is unprojected (Standard) and is
used to create the second set (Projected). The difference between the two options is that when
you choose Projected, the first set of files (Standard) is deleted once the projection process is
complete.
A Note on Projecting 250m Data
In order to perform bowtie correction on 250m data, you must change your Image Tile Size in
the ENVI Preferences dialog (under Miscellaneous) to a value of at least 10.0 MB. If this is not