Bug report #14678

Raster calculator fails with large raster in QGIS 2.14.1

Added by john coleman about 4 years ago. Updated over 1 year ago.

Status:Closed
Priority:Normal
Assignee:-
Category:Raster Calculator
Affected QGIS version:2.14.1 Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:fixed/implemented
Crashes QGIS or corrupts data:No Copied to github as #:22642

Description

I'm working in QGIS 2.14.1 with a DEM ranging from 200 feet to 1600 feet elevation called "dem_3m_Zft1b" (geotiff, 16822 X 33349 cells, No-data =-9999)

If I enter "dem_3m_Zft1b" > 0

in the raster calculator I get a result that has a value of 0 everywhere in the raster extent. The calculator does not seem to recognize the existence of any values or of the no-data flag.

With a subset/portion of the DEM called "[email protected]" (4489 X 6175 cells, No-data=-9999), If I enter "[email protected]" > 0 in the raster calculator I get a result that has a value of 1 where there was data and a value of no-data where there was no-day. Everything seems OK when using the subset.

The larger DEM "dem_3m_Zft1b" seems OK in other ways, e.g. the "Identify" tool finds valid values for Band1, but the raster calculator doesn't seem to recognize the data in it.

I tried the same operation on the large DEM in the Processing Toolbox, SAGA, Raster Calculator with the syntax: g1 > 0 and I get the correct results, i.e. 1 where there is data and no-data where there isn't.

History

#1 Updated by Giovanni Manghi about 4 years ago

  • Category set to Raster Calculator

#2 Updated by Giovanni Manghi about 4 years ago

There is (was?) already a ticket on this matter, but now I can't find it. If is still open this should merged with that one.
Meanwhile just use SAGA or GRASS rastercalc, they are much more reliable and robust.

#3 Updated by john coleman about 4 years ago

in the bug report;
If I enter "dem_3m_Zft1b" > 0
should read:
If I enter "[email protected]" > 0

#4 Updated by Giovanni Manghi about 3 years ago

  • Regression? set to No
  • Easy fix? set to No

#5 Updated by Nyall Dawson over 1 year ago

  • Resolution set to fixed/implemented
  • Description updated (diff)
  • Status changed from Open to Closed

This was fixed in 3.4

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