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With QGIS 2.14.3 I am attempting to convert a raster layer to a binary layer, using a certain threshold. With some layers I can use this formula in the Raster Calculator and get the expected output;

"raster@1" < 0.994 = 0 AND "raster@1" > 0.994 = 1

But when I try it with another layer the output is either all nan or all 0's. I've tried saving it in a different format (.img instead of .tif) as suggested in another answer here, but get the same result.

Is there a mistake I'm making with this?

Or an obvious reason it might give this output?

Or maybe the raster is just corrupted in some way?

(The imagery is the output from a long process, and confidential, so I can't share the actual file).

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  • Could you try "raster@1" >= 0.994? Actually this should procure the same output.
    – Erik
    Commented Sep 24, 2018 at 9:04

1 Answer 1

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You are asking an impossible question, raster@1 cannot be less than 0.994 AND greater than 0.994 at the same time. I would change it to

"raster@1" < 0.994 = 0 OR "raster@1" >= 0.994 = 1
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  • Perhaps I misunderstand how the Raster Calculator works? Cells within the raster can have values of less than and greater than 0.994. I have used the formula as written above with AND, which gave the expected output.
    – EcologyTom
    Commented Sep 24, 2018 at 14:33

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