This command allows to import SPOT-4 Take5 products.
There are two levels of products that can be imported:
- Level 1C : Top of Atmosphere reflectance ortho-rectified product
- Level 2A : Surface reflectances and cloud mask
The products can be either compressed in a tar archive, or uncompressed in a specific folder structure.
Wheter the product is an archive or a folder, the list of files must have the same structure:
For Level 1C, the product must contain 2 files and a MASK directory containing a mask file:
-
the xml file provides the image metadata
-
the TIF file provides the bands (XS1, XS2, XS3, SWIR) coded as signed 16 bits integers
- the saturated pixel mask _SAT.TIF contains an 8 bit information:
- Bit 0 is XS1 saturated pixel mask
- Bit 1 is XS2 saturated pixel mask
- Bit 2 is XS3 saturated pixel mask
- Bit 3 is SWIR saturated pixel mask
For Level 2A, the product must contain 3 files and a MASK directory containing multiple mask files:
-
the xml file provides the image metadata
-
the two .TIF files in GeoTiff format that provide surface reflectances, corrected from atmospheric effects, including adjacency effects (ORTHO_SURF_CORR_ENV, not provided for LANDSAT) and even terrain effects (ORTHO_SURF_CORR_PENTE).
- A saturated pixels mask _SAT.TIF (as in Level 1C)
- A mask of clouds and cloud shadows _NUA.TIF
- bit 0 (1) : all clouds (except thin ones) or shadows
- bit 1 (2) : all clouds (except thin ones)
- bit 2 (4) : cloud detected through absolute threshold
- bit 3 (8) : cloud detected through multi-t threshold
- bit 4 (16) : very thin clouds
- bit 5 (32) : high clouds detected with 1.38 µm band (LANDSAT 8 only)
- bit 6 (64) : cloud shadows matched with a cloud
- bit 7 (128) : cloud shadows in the zone where clouds could be outside the image (less reliable)
- Diverse binary masks : water, snow and no_data mask, plus (V2.0) pixels lying in terrain shadows _DIV.TIF
- bit 0 (1) : No data
- bit 1 (2) : Water
- bit 2 (4) : Snow
- bit 3 (8): V2.0 only : Sun too low for terrain correction (limitation of correction factor that tends to the infinity, correction is false)
- bit 4 (16): V2.0 only : Sun too low for terrain correction (correction might be inaccurate)
For detailed information about this format, please have a look at the following link: