[GRASS-dev] Update manual for "i.oif"

[Nikos Alexandris]

Nikos A wrote:

> > The manual of i.oif refers to LANDSAT TM bands 1-5, & 7.  Why not for
> > newer Landsat products, e.g. ETM+?

Markus N:

> Nobody picked it up so far... :)

> > Can/should we update the manual?
> > <http://grass.osgeo.org/grass70/manuals/i.oif.html>

> Please go ahead, thanks.

I wonder if (and how) we should alter the parameters descriptions as well. I 
mean, the OIF concept is (in theory) applicable to any three-band/image 
combination (let them be spectral bands or else, given they are in the same 
unit). 

Proposed changes for the manual:

--%<---
svn diff i.oif.html
Index: i.oif.html
===================================================================
--- i.oif.html  (revision 56333)
+++ i.oif.html  (working copy)
@@ -1,16 +1,18 @@
 <h2>DESCRIPTION</h2>
 
-<em>i.oif</em> calculates the Optimum Index Factor for LANDSAT TM bands 
1,2,3,4,5 and 7.
-<p>The Optimum Index Factor is calculated to determine the band combination 
which
-shows the maximum information when combined into a composite image. The bands
-comprising the highest scoring combination from <em>i.oif</em> are used as 
the 
-three color channels required for <em>d.rgb</em> or <em>r.composite</em>.
+<em>i.oif</em> calculates the Optimum Index Factor for multi-spectral 
satellite imagery.
+<p>The Optimum Index Factor (OIF) determines the three-band combination that
+maximizes the variability (information) in a multi-spectral scene. The index 
is
+a ratio of the total variance (standard deviation) within and the correlation
+between all possible band combinations. The bands that comprise the highest
+scoring combination from <em>i.oif</em> are used as the three color channels
+required for <em>d.rgb</em> or <em>r.composite</em>.
 <p>The analysis is saved to a file in the current directory called 
"i.oif.result".
 
 
 <h2>NOTES</h2>
 
-Colour Composites in BGR order: important band combinations (example: 
+Colour Composites in BGR order: important Landsat TM band combinations 
(example: 
 234 in BGR order means: B=2, G=3, R=4):
 
 <ul>
@@ -29,7 +31,7 @@
 
 <li> 345: contains one band from each of the main reflective units (vis, nir,
 shortwave infra). Green vegetation is green and the shortwave band shows
-vegetational stress and mortality. Roads are less evident as band 3 is blue.
+vegetation stress and mortality. Roads are less evident as band 3 is blue.
 
 <li> 347: similar to 345 but depicts burned areas better.
 <li> 354: appears more like a colour infrared photo.
--->%--

Thanks, Nikos