[GRASS-SVN] r69367 - sandbox/alexandris/i.rgb.his

[svn_grass at osgeo.org]

Author: nikosa
Date: 2016-09-04 11:16:06 -0700 (Sun, 04 Sep 2016)
New Revision: 69367

Added:
   sandbox/alexandris/i.rgb.his/COMMENTS
Log:
i.rgb.his (sandbox): added COMMENT with examples for various bitnesses

Added: sandbox/alexandris/i.rgb.his/COMMENTS
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--- sandbox/alexandris/i.rgb.his/COMMENTS	                        (rev 0)
+++ sandbox/alexandris/i.rgb.his/COMMENTS	2016-09-04 18:16:06 UTC (rev 69367)
@@ -0,0 +1,42 @@
+# Bitness
+
+Below, examples on setting the bit_depth according to the input data's bitness
+
+
+## 11-bit
+
+For 11-bit sensors, like  QuickBird2 [0], set `bit_depth=11`. For example:
+
+i.rgb.his r=Red g=Green bl=Blue h=h s=s l=l bit_depth=11 --o
+
+
+## 12-bit
+
+?
+
+
+## 16-bit
+
+Landsat 8 instruments OLI and TIRS are capable of 12-bit. Products are,
+however, delivered as 16-bit images (scaled to 55,000 grey levels). [0]
+
+Therefore, the bitness needs to be set to 16, like:
+
+i.rgb.his red=B4.hpf green=B3.hpf blue=B2.hpf h=h s=s l=l bit=16
+
+
+# Arbitrary lower bit depts
+
+The module also allows for data of less than 8-bit. For example, data from
+NOOA's DMSP OLS (Operational Linescan System), which features 6-bit sensors [2].
+
+For example:
+
+i.rgb.his r=F152007 g=F152005 bl=F152004 h=h s=s l=l --o bit=6
+
+
+# References
+
+[0]
+[1] http://landsat.usgs.gov/landsat8.php
+[2] http://ngdc.noaa.gov/eog/sensors/ols.html