1i.landsat.acca(1)           GRASS GIS User's Manual          i.landsat.acca(1)
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NAME

6       i.landsat.acca   -  Performs  Landsat  TM/ETM+  Automatic  Cloud  Cover
7       Assessment (ACCA).
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KEYWORDS

10       imagery, ACCA, cloud detection, satellite, Landsat
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SYNOPSIS

13       i.landsat.acca
14       i.landsat.acca --help
15       i.landsat.acca   [-5fx2s]   input=basename   output=name    [b56compos‐
16       ite=float]     [b45ratio=float]    [histogram=integer]    [--overwrite]
17       [--help]  [--verbose]  [--quiet]  [--ui]
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19   Flags:
20       -5
21           Data is Landsat-5 TM
22           I.e. Thermal band is ’.6’ not ’.61’)
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24       -f
25           Apply post-processing filter to remove small holes
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27       -x
28           Always use cloud signature (step 14)
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30       -2
31           Bypass second-pass processing, and merge warm (not  ambiguous)  and
32           cold clouds
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34       -s
35           Include a category for cloud shadows
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37       --overwrite
38           Allow output files to overwrite existing files
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40       --help
41           Print usage summary
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43       --verbose
44           Verbose module output
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46       --quiet
47           Quiet module output
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49       --ui
50           Force launching GUI dialog
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52   Parameters:
53       input=basename [required]
54           Base name of input raster bands
55           Example: ’B.’ for B.1, B.2, ...
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57       output=name [required]
58           Name for output raster map
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60       b56composite=float
61           B56composite (step 6)
62           Default: 225.
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64       b45ratio=float
65           B45ratio: Desert detection (step 10)
66           Default: 1.
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68       histogram=integer
69           Number of classes in the cloud temperature histogram
70           Default: 100
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DESCRIPTION

73       i.landsat.acca  implements  the Automated Cloud-Cover Assessment (ACCA)
74       Algorithm from Irish (2000) with the constant values  for  pass  filter
75       one from Irish et al. (2006). To do this, it needs Landsat band numbers
76       2, 3, 4, 5, and 6 (or band 61 for Landsat-7 ETM+)  which  have  already
77       been  processed  from  DN  into reflectance and band-6 temperature with
78       i.landsat.toar).
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80       The ACCA algorithm gives good results over most of the planet with  the
81       exception  of  ice  sheets  because  ACCA  operates on the premise that
82       clouds are colder than the land surface they cover. The  algorithm  was
83       designed  for Landsat-7 ETM+ but because reflectance is used it is also
84       useful for Landsat-4/5 TM.
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NOTES

87       i.landsat.acca works in the current region settings.
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EXAMPLES

90       Run the standard ACCA algorithm with filling of small cloud holes  (the
91       -f  flag):  With  per-band reflectance raster maps named 226_62.toar.1,
92       226_62.toar.2,  [...] and LANDSAT-7 thermal band  226_62.toar.61,  out‐
93       putting to a new raster map named 226_62.acca:
94       i.landsat.toar sensor=7 gain=HHHLHLHHL date=2003-04-07 \
95         product_date=2008-11-27 band_prefix=226_62 solar_elevation=49.51654
96       i.landsat.acca -f band_prefix=226_62.toar output=226_62.acca
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REFERENCES

99       1      Irish  R.R.,  Barker  J.L.,  Goward S.N., and Arvidson T., 2006.
100              Characterization of the  Landsat-7  ETM+  Automated  Cloud-Cover
101              Assessment  (ACCA)  Algorithm.  Photogrammetric  Engineering and
102              Remote Sensing vol. 72(10): 1179-1188.
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104       2      Irish, R.R., 2000. Landsat 7 Automatic Cloud  Cover  Assessment.
105              In  S.S. Shen and M.R. Descour (Eds.): Algorithms for Multispec‐
106              tral, Hyperspectral, and Ultraspectral Imagery  VI.  Proceedings
107              of SPIE, 4049: 348-355.
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SEE ALSO

110        i.atcorr, i.landsat.toar
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AUTHOR

113       E.  Jorge  Tizado  (ej.tizado unileon es), Dept. Biodiversity and Envi‐
114       ronmental Management, University of León, Spain
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SOURCE CODE

117       Available at: i.landsat.acca source code (history)
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119       Main index | Imagery index | Topics index | Keywords index |  Graphical
120       index | Full index
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122       © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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126GRASS 7.8.5                                                  i.landsat.acca(1)