In pixel space the data can be manipulated to make a new data set in
the following ways:
(1) using every nth value,
(2) limiting the data to within a rectangular region, or
(3) resampling to an arbitrary size.
In metadata space the data can be manipulated to make a new data set
in the following ways:
(1) selecting new endpoints for the original metadata to assume.
(2) resampling to an arbitrary size.
(3) registering (i.e. matching up geographic boundaries) one dataset to the other.
These (when logical) can be combined.
Only datasets that have explicit or implied geo-referencing (i.e. geographic) information can be registered. Examples of explicitly geo-referenced data sets are HDF-EOS point, grid and swath files and PDS files that have projection information. An example of an implied geo-referenced dataset is a raw binary file where the metadata is supplied by the user and the metadata labels are "Latitude" and "Longitude".
Registering two datasets that are projected will result in the destination datasets projection information being used by the source dataset. (e.g. if it is desired that a sinusoidal projected data be registered to Lambert projected data, the data in the sinusoidal projection will be reprojected into the Lambert projection.)
If two geo-referenced datasets are registered but there are no common geographic areas, then no data will appear for the dataset whose metadata is outside the selected region.
Regrid is useful when a data set is very large and the region of interest in it is small. Its output is available through the drag and drop button(s) that will appear once the "Accept" button is pressed.
The Reset button resets input values to the original values from the dataset that was dropped in.
The Menu button allows the user to switch between resampling in pixel space and resampling in metadata space. If there have been two datasets dropped in and they are recognized as being able to be registered then the menu will present options to register one dataset to the other.
The "Start:" and "End:" fields set the limits of the data. The "Step:" field is used for decimation; a value of n here means every nth value of the old data set will be mapped into the new data set. The "Resample:" fields allow the user to set what the dimensions of each axis should assume.
The "Start:" and "End:" fields set the limits which the new metadata should assume. The "Resample:" fields allow the user to set what the dimensions of each axis should assume.
If you decimate an axis, remember that the values in the "Resample:" boxes are the final size of the new data set, so set them to the values you want.
Up to two datasets can be managed at one time. This is especially useful for data that have overlapping geographic regions, but may have different resolutions.
If you are subsetting or resampling a dataset that has projection information and the resolution of the data is changed so that the projection parameters no longer have meaning (e.g. resampling axes so the resolution on the x-axis is different than the resolution on the y-axis) there will not be any projection information supplied in the output dataset.
If you have a 4D dataset, the 4th axis sliders/text pads can be used to specify a slice on the 4th axis. If you don't choose a slice this way, you will see only the first slice of this 4th axis.