Sentinel 2 Imagery
This is a European Space Agency (ESA) satellite.
Data is available or
Copernicus Open Access Hub (Directions) .
There are two satellites on opposite sides of the earth, and each revisits the
same locations every 10 days, so one will visit every 5 days. Imagery is
acquired at 1030 local time, which minimizes the effect of shadows while
also minimizing potential cloud cover. This is the close to the same time
as Landsat and SPOT-5, allowing integration with their archive for time-series
studies.
First data in 2015.
Multiple resolutions complicates intelligent display (unlike Landsat, which
provides the TIR bands at the same resolution, with only the Pan band a
different size)
Landsat versus Sentinel-2
Bands and resolution
To identify the desired tile(s)
Complex data structure, JP2 file format; the imagery is buried 4 levels down
in directories with very long names. You should use folder selection to
pick scenes.
- L1C_T32NNF_A009285_20170402T093844\--top level directory, with the key
information
- L1C: Multispectal imagery, level 1C for this image
- T32NNF--tile number in MGRS
- 20170402T093844--date acquired Year-Month-Day-Hours-Minutes-Sconds
- S2A_MSIL1C_20170402T093031_N0204_R136_T32NNF_20170402T093844.SAFE\
- S2A: Sentinel-2, the A satellite (A/B currently flying)
- MSIL1C: Multispectal imagery, level 1C for this image
- 20170402T093031: date imagery acquired, date acquired
Year-Month-Day-Hours-Minutes-Sconds
- N0204--baseline processing number
- R136: Relative orbit number, 1-143; there are all descending orbits
in sequential order, so the next one will be displaced quite a distance
to the west
- T32NNF--tile number in MGRS
- 20170402T093844
- SAFE\--Sare Archive Format for Europe. Some software wants you
to load this directory; which may decompress under another
directory with some of the same information in a different format
- GRANULE\L1C_T32NNF_A009285_20170402T093844\
- IMG_DATA\
- T32NNF_20170402T093031_B08.jp2
Level
- 1C: top of atmosphere reflectance
- 2A: bottom of atmosphere reflectance, with three folders with the 10,
20, and 60 m data. This has an addtional folder after IMG_DATA with
the resoluution (R10m, R20m, and R60m), and the band files have "_10m" after
"_B02". Only the 10 m folder has Band 8; the others have Band 8A.
Download available from
Copernicus Open Access Hub
MICRODEM will use
GDAL
to convert the JP2 files to Geotiff .
There is an option on the Imagery tab of the options form on whether to keep the
JP2 files (needed if you want to use
ACOLITE) .
- The L1C tile JP2 files for a scene take about 800 MB, but require about a minute
with GDAL before they can be used by MICRODEM.
- The Geotiffs take about 1.6 GB.
Working with Sentinel-2 in MICRODEM
- Two ways to use in MICRODEM so you
can combine bands and do analysis.
- If the program does not recognize a Sentinel-2 image, put the data in a
directory with the word "SENTINEL" somewhere in the
path.
- Insure you have GDAL to convert
the JPEG2000 files
- If you have a lot of scenes, you can do a batch conversion and take
a walk while they process. File, Tools, Sentinel 2 data prep. Pick a directory, and all images
in the first level of subdirectories will be extracted.
- File, Open submenu, Open Landsat/Sentinel-2 multiband image: particularly good for
Sentinel-2 which buries the image files many directories deep.
Will let you pick the high level directory, GDAL convert the bands from JP2
to Geotiff. This will take some time for the conversion.
Metadata:
References
Using in QGIS:
Last revision 11/25/2022