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I have a crop data raster layer in QGIS with one band with values from 10 to 230.

I have written an expression in the Raster Calculator to keep only a number of values (e.g. when = 145 OR when = to 146, etc..

This works but the resulting layer has 0 values for areas that did not satisfy the expression and 1's for areas that did. As a result, I appear to have lost the original raster values which indicate crop types.

Am I doing this wrong or maybe there's another way to filter that will keep my original values?

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  • Sorry, the question is unclear. If you have 145, you want to get 145. for 146 -> 146. But what values do you want to have for 10, 50, 100 etc.?
    – Babel
    Commented Jan 10, 2022 at 22:19
  • Sorry I was unclear...those other values I'm not interested in can be 0. So for example: 10--->0 20-->0 140-->140 145--->145 190--->0 etc.
    – Carlos Pelay
    Commented Jan 10, 2022 at 22:50

1 Answer 1

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If you use QGIS 3.22 or later, you have the new conditional if in raster calculator:

IF ("RASTER@1" >= 145 AND "RASTER@1" <= 146, "RASTER@1", 0)

For older versions, use:

("RASTER@1" >= 145 and "RASTER@1" <= 146) * "N45E006@1"

I would not advice using something like "RASTER@1" = 145 or "RASTER@1" = 146: probably pixel values will not match exactly integers (145.00, 146.00), but be rather like 145.7 and using this expression, it will not find anything.

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  • Thanks @Babel I'll try that. SO would that keep those values as 145 or 146 and all other values set to 0?
    – Carlos Pelay
    Commented Jan 11, 2022 at 0:18
  • It keeps all values from 145 to 146 and sets all others to 0
    – Babel
    Commented Jan 11, 2022 at 6:21
  • Thanks @Babel this worked perfectly!
    – Carlos Pelay
    Commented Jan 11, 2022 at 23:24

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