Reclassifying Landsat Cloud Masks

[André Beig]

Hello everyone, 

I'm trying to reclassify Landsat cloud masks in so that the values are 0 for areas with clouds, cloud shadows and snow and 1 for everything else, is there any rsgislib script that accomplishes that, I couldn't find any, but I'm new to the library, so maybe I was just looking in the wrong places.

thanks.

[Pete Bunting [pfb]]

Hello,

Try using the imageMath function and include if statements. The syntax for the maths expressions is muparser(http://beltoforion.de/article.php?a=muparser&hl=en&p=features&s=idDef1#idDef1)

The following expression is assuming your cloud, snow and cloud shadow pixels have values 1, 2 or 3. If any of those are true then set the output value as 0 otherwise 1.

import rsgislib
from rsgislib import imagecalc
imagecalc.imageMath(in.kea, out.kea, ‘(b1==1) || (b1==2) || (b1==3)?0:1', 'KEA', rsgislib.TYPE_8UINT)


If you have multiple input image bands then use rsgislib.imagecalc.bandMath.

Best wishes,

Pete
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> On 22 Mar 2017, at 17:57, André Beig <beig...@gmail.com> wrote:
>
> I'm trying to reclassify Landsat cloud masks in so that the values are 0 for areas with clouds, cloud shadows and snow and 1 for everything else, is there any rsgislib script that accomplishes that, I couldn't find any.
>
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[André Beig]

Thank you Pete, that worked just fine, I was trying to use imageMath but didn't know how to use the syntax correctly, so I assumed that I was supposed to use something else, now that's resolved!