[Qgis-user] NDVI creation from LANDSAT
john polo
jpolo at mail.usf.edu
Fri Feb 13 10:11:35 PST 2015
Users,
I have data for LANDSAT 8. I am trying to create an NDVI raster. I used
the raster calculator and the following equation:
( "LC80260352013188LGN00_sr_band5 at 1" -
"LC80260352013188LGN00_sr_band4 at 1" ) / (
"LC80260352013188LGN00_sr_band4 at 1" + "LC80260352013188LGN00_sr_band5 at 1" )
where band 5 is IR and band 4 is red. The image is grey scale, the bands
appear that way to start as well, and the values are between 0 and 1,
when I thought they'd be between -1 and 1. I am a novice with this, but
I am expecting reds and greens. Mostly greens in my case since I am
working with a forest. Is this correct?
I searched a little and this older email from the listserv gave me an
inkling of what I may need to do:
"... you have to apply an atmospheric correction (I had to ...) with the
TOA plugin in QGIS. In this case you need the *.met file for the
correction, too."
http://lists.osgeo.org/pipermail/qgis-user/2014-June/028050.html
I looked in the plugins and there is nothing for "TOA", which I assume
means top of atmosphere, or "Top" or "atmosphere", so I don't know what
plugin this refers to. Nor do I know if that will even do whatever I
need done to change my image.
John Polo
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