Bug report #18705

Updating raster single-band min/max method does not update actual min/max

Added by Dewey Dunnington over 4 years ago. Updated over 4 years ago.

Category:OsX UI
Affected QGIS version:3.0.0 Regression?:No
Operating System:OSX Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:26593


When updating the min/max method for single band (pseudocolor and grayscale), updating the manual min/max values will change the method to "User defined", but changing the method type to something else (min/max, mean +/-) does not update the min/max values until the "Apply" or "OK" is clicked on the user dialog. Clicking "Classify" doesn't do anything. Is this intentional? I think there used to be a "calculate" button here? It took me a while to figure out the fix...

Screen Shot 2018-04-10 at 4.33.00 PM.png (327 KB) Dewey Dunnington, 2018-04-10 09:48 PM

Screen Shot 2018-04-11 at 1.52.21 PM.png (528 KB) Dewey Dunnington, 2018-04-11 06:56 PM


#1 Updated by Alessandro Pasotti over 4 years ago

  • Assignee set to Alessandro Pasotti

Can you please check how (and if) it was working in 2.x?

If this is a regression introduced in 3.x, please flag it.

What is the expected behavior here?

I think that the "Classify" button should recalculate the values whenever pressed...

#2 Updated by Alessandro Pasotti over 4 years ago

  • Assignee deleted (Alessandro Pasotti)

Small update testing on Linux, if I manually change Min or Max values this is what happens:

- User defined is automatically selected
- The values are automatically recalculated

this looks like (another) OSX issue, sorry but I cannot help.

#3 Updated by Dewey Dunnington over 4 years ago

This is not an OSX issue, this is a QGIS 3 issue. Updating the min/max values manually will automatically change the min/max method type, but changing the min/max method type does not automatically change the min/max values unless the "Apply" or "OK" is clicked. In QGIS 2, there was a "Load" button that performed this operation. This is a problem for both grayscale and pseudocolor singleband representations.

#4 Updated by Alessandro Pasotti over 4 years ago

  • Assignee deleted (Alessandro Pasotti)

#5 Updated by Alessandro Pasotti over 4 years ago

ok, got it.
The load button is gone.

Apparently by design:

commit 407991ed35049ec267c4641751841b4631f9c05e
Author: nirvn <>
Date: Tue Dec 27 14:43:26 2016 +0700

[ui] rename the min/max widget group box title
Since there is no more loading involved through
the min/max widget, rename it to:
"Min /max values settings"

#6 Updated by Dewey Dunnington over 4 years ago

No problem with a Load button that doesn't exist, provided that there is a way to change from a manually entered min/max to a calculated min/max. The "load" operation is fired when "Apply" is clicked, but could also be fired when the user changes any of the options for the Min/Max settings (e.g., different +/- standard deviation, change to min/max from user defined). At the very least, I feel like it should be fired when the user clicks "classify" in the pseudocolor section.

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