ACOLITE supports the processing of both L1C scenes and granules. L1C scenes are made up out of a series of granules in the SAFE format, see the figure below for an example. Granules are currently not distributed separately by ESA, but can be extracted from the L1C scene. USGS distributes L1C granules via EarthExplorer.
The figure below shows the structure of an L1C scene taken 2016-03-14 covering Lake Balaton (red rectangle) in Hungary. This scene consists of 13 granules, 9 in UTM zone 33, 4 in UTM zone 34.
- L1C_granules.png (348.14 KiB) Viewed 11114 times
When no region limits are provided, ACOLITE will process the given granule or all the granules within the scene separately. When region limits are provided, ACOLITE can process the granules covering the region separately, or stitch together the granules from the same UTM zone. In the example above, the four named granules would be processed if the coordinates of the red bounding box were provided. When stitching is requested the ACOLITE output will cover the region.
The figure below shows the data covering Lake Balaton, stitched together from 4 separate granules. The yellow lines illustrate the granule borders.)
- balaton_stitched.png (573.17 KiB) Viewed 11114 times
As processing of full granules or scenes can be lengthy, providing a relatively limited region of interest is recommended. Reprojection of data from adjacent UTM zones is planned for a future version of ACOLITE.