NAME

       i.in.spotvgt  - Imports SPOT VGT NDVI data into a raster map.

KEYWORDS

       imagery, import

SYNOPSIS

       i.in.spotvgt
       i.in.spotvgt --help
       i.in.spotvgt   [-a]   input=name   [output=name]    [--overwrite]   [--help]   [--verbose]
       [--quiet]  [--ui]

   Flags:
       -a
           Also import quality map (SM status map layer) and filter NDVI map

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=name [required]
           Name of input SPOT VGT NDVI HDF file

       output=name
           Name for output raster map

DESCRIPTION

       i.in.spotvgt imports SPOT Vegetation (1km, global)  NDVI  data  sets.   After  import  the
       digital  numbers  (DN)  are remapped to VEGETATION NDVI values and the NDVI color table is
       applied. The imported DN map is removed after remapping.

       Apparently missing raster cells due to bad pixel quality are  reconstructed  by  the  SPOT
       operating  team  in  the NDVI file. The differences between the filtered (-a flag) and raw
       NDVI map should be compared.

NOTES

       The SPOT VGT files are delivered in HDF4 (Hierarchical Data Format Release 4)  format.  It
       is required to have the GDAL libraries installed with HDF4 support.

   Export of entire world SPOT VGT maps
       When  working  with SPOT VGT with entire world extent, it is recommended to zoom to w=180W
       and e=180E instead of using the map extent for map export. These  entire  world  SPOT  VGT
       data  are  exceeding -180.0 degree which can lead to unhelpful large East-West coordinates
       in the exported file. It is also recommended to then use an export command which  respects
       the user settings. Example:
       # import:
       i.in.spotvgt 0001_NDV.HDF
       # export:
       g.region w=180W e=180E n=75:00:16.071429N s=56:00:16.069919S res=0:00:32.142857 -p
       r.out.gdal 0001_NDV format=GTiff out=spotndvi.tif

SEE ALSO

        r.in.gdal, r.out.gdal

REFERENCES

       SPOT Vegetation (1km, global) NDVI data set server
       SPOT Vegetation FAQ
       1.13 How must I read the 8 bits of the status map? - Quality map

AUTHOR

       Markus Neteler

       Last changed: $Date: 2013-05-11 15:23:40 +0200 (Sat, 11 May 2013) $

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