Raster Calculator not giving the correct raster from a slope percentage raster

[qgib]

Author Name: Prime Enrique Rendon (Prime Enrique Rendon)
Original Redmine Issue: 11350
Affected QGIS version: 2.4.0
Redmine category:raster_calculator

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i have a srtm_62_11 downloaded from the internet with WGS84 projection. I tried to derived slope raster from the srtm (DEM) as percentage instead of degrees and a z-factor of 113200 to convert degrees in meters (please correct me in this factor) using the Raster>>Analysis>>DEM(Terrain models). i have successfully made the slope raster with 0.607858 and 62.4067 as min and max values (i believe its in percentage. However when i try to use the raster calculator to derived a new raster with slope of less than or equal to 8 ("slope%@1" <= 8 using this expression), i didn't get the correct values. i only get a 0 and .999 as min and max values for the new raster.

Am i doing the right procedure or an error in the process? I'll appreciate your help.thanks

[qgib]

Author Name: Nicolas Cadieux (@NicolasCadieux)

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I think you are getting 0 and 1. 0 for cells that don't meet the requirements and 1 where the cells do. You then need to multiply that by your slope layer so that the 1 get multiplied by the slope values and the 0 stay zeros...

[qgib]

Author Name: Prime Enrique Rendon (Prime Enrique Rendon)

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how can i multiple the said values to my slope? but i'm still looking for ways to multiply it. thanks for the reply.

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

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An expression like:

("slope%@1" <= 8 ) * "slope%@1"

will work

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• resolution was changed from to invalid
• status_id was changed from Open to Closed