Preparing data for atmospheric correction

Before you begin setting up the atmospheric-correction process, ingest your data as described in the following table. By doing so, you ensure that all the required metadata is retrieved properly from the satellite data. Ingesting data also updates many of the fields in the atmospheric-correction workflows, saving you from having to enter the information manually.

Table 1 identifies the supported satellites and the required algorithm or entry method for ingesting data for each.

Table 1. Supported sensors and ingest method
Sensor Ingest method
ALI (Advanced Land Imager) Manual entry
ALOS AVNIR-2 CDALOS algorithm
ASTER CDASTER algorithm
CBERS-4 GDB (Open key file *.xml)
Deimos-1 GDB (Open key file *.dim)
Deimos-2 GDB (Open key file *.dim)
DMC (Disaster Monitoring Constellation) CDDMC algorithm
FASat Charlie GDB (Open key file *.dim)
Formosat-2 CDFORMOSAT algorithm
Formosat-2 (DIMAP) GDB (Open key file *.dim)
GeoEye-1 (TIFF or NITF - Old Format) CDIKONOS algorithm
GeoEye-1 (*metadata.txt) GDB (Open key file *metadata.txt)
Gaofen-1 GDB (Open key file *.xml)
Gaofen-2 GDB (Open key file *.xml)
Ikonos-2 (TIFF or NITF - Old Format) CDIKONOS algorithm
Ikonos-2 (*metadata.txt) GDB (Open key file *metadata.txt)
IRS-A/B/C/D/P6 Manual entry
Jilin-1 07B GDB (Open key file *_meta.xml)
Kazeosat-2 GDB (Open key file *.dim)
Kompsat-2 GDB (Open key file *.eph)
Note: Calibration coefficients provided in the metadata are placeholders. Select one of the calibration files provided in the actor\cal\kompsat-2 folder of your CATALYST Professional installation.
Kompsat-3/3A GDB (Open key file *Aux.xml)
Landsat-4 and 5 MSS (*HDF.TIF) CDLAND7 algorithm
Landsat-4 and 5 MSS (*MTL.TXT) GDB (Open key file *MTL.txt)
Landsat-4 and 5 TM (*HDF.TIF) CDLAND7 algorithm
Landsat-4 and 5 TM (*MTL.TXT) GDB (Open key file *MTL.txt)
Landsat-7 ETM+ (*HDF.TIF/*HDF.L1G) CDLAND7 algorithm
Landsat-7 ETM+ (*MTL.TXT) GDB (Open key file *MTL.txt)
Landsat-8 (*MTL.TXT) GDB (Open key file *MTL.txt)
Orbview-3 (TIFF or NITF) CDOV algorithm
PlanetScope GDB (Open key file *_metadata.xml)
Pleiades GDB (Open key file *.xml)
QuickBird GDB (Open key file *.imd or *.xml)
RapidEye GDB (Open key file *metadata.xml)
Resourcesat-2 GDB (Open key file *BAND_META.txt)
SAC-C Manual entry
Sentinel-2 GDB (Open key file S2*.xml or manifest.safe)
SPOT-1, 2, and 3 (CAP) CDSPOTRPC algorithm
SPOT-4 and 5 (CAP) CDSPOTRPC or CDSPOT5 algorithm
SPOT-1 to 5 (DIMAP) GDB (Open key file *.dim)
SPOT-6 and 7 GDB (Open key file *.xml)
Thaichote (THEOS) GDB (Open key file *.dim)
TripleSat GDB (Open key file *.xml)
WorldView-2 GDB (Open key file *.imd)
WorldView-3 GDB (Open key file *.imd)
ZY3 GDB (Open key file *.xml)
ZY3-2 GDB (Open key file *.xml)
Note: With GDB formats, select the GDB key file name to open in Focus.

To retrieve the sensor metadata and information about image acquisition, import your images from the CD using the appropriate CD-read algorithm. Most sensors have a specific CD-read algorithm that creates a PCIDSK file, imports the imagery channels from the CD, extracts the metadata, and then saves the satellite path information in a segment. When you prepare your imagery this way, Focus can set or calculate automatically several parameters when you configure the atmospheric correction workflows.

The number and types of bands on the CD depends on the sensor used to capture the data. Typically, the visible, thermal, and panchromatic bands are in different resolutions. Some sensors may not provide thermal or panchromatic bands. Read the bands of the same resolution at the same time into one file.

For example, Landsat 7 data usually has eight bands: bands 1 to 5 and 7 are the visible wavelengths with a 30-meter resolution, band 6 contains two thermal wavelengths with a 60-meter resolution, and band 8 is the panchromatic with a 15-meter resolution. Use the CDLAND7 algorithm to read bands 1 to 5 and 7 into a file, then band 6 into a file, and then band 8 into a file. If you do not intend to use the thermal or panchromatic bands in the atmospheric correction process, you do not need to read those bands into a file.

The CD-read algorithms are available with EASI, Modeler, and Focus.

To retrieve metadata using CD-read algorithms in Focus

  1. On the Tools menu, click Algorithm Librarian.

    The Algorithm Librarian window appears for the selected for the algorithm

  2. Expand the Data Interchange folder, and then in the CD Reading/Utilities folder, click the the appropriate CD-read algorithm for the sensor data.
  3. Click Open.

    The Module Control Panel window appears for the selected algorithm.

  4. On the Files and Input Parameters tabs, type or select information for each parameter, as applicable.
  5. Click Run.
  6. Repeat this procedure for each set of bands with the same resolution.

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