[Qgis-developer] Getting ready to branch QGIS 0.11.0

[Peter Ersts]

First off, sorry for my total lack of contribution over the last couple 
of months it has been a hectic spring...

Tim Sutton wrote:
> Peter: could you look at the raster tests? Currently 3 tests fail. 
>
> Could you confirm if it is your idea that we should mandate histogram
> stretch definition explicitly now, whether it should be set to min /
> max using band limits by default and this is a bug, or if something
> else is afoot here that I'm missing? 
First test - Grayscale Image: The default contrast enhancement when the 
QSettings value was not found was incorrectly set in revision 8398 when 
I added the override functionality. As generally agreed upon, it should 
have been set to a min max enhancement for comfort of newer users. I 
have committed the change. However, this test can still fail if you have 
set a different enhancement to be your default (check the raster 
properties dialog, lower right, initial tab)

> I'm going to look at the other
> two failed raster tests tomorrow and see if I can work out why they
> fail.
>   

I see three possible places for problems, none of which may actually be 
a bug, just a difference in rendering since the test/result  images were 
first generated
1) Again, your chosen default contrast enhancement may be causing a 
conflict (but should not be an issue with the third test because a qml 
file is being loaded)

2) The image now loads on the first pass with an estimated min max 
rather than calculated values. One band in each of these two tests does 
show differences between the estimated min max and actual min max -- 
again this should not be an issue with the third test since a qml file 
is being loaded

3) There has been a change with the how the default extent is 
determined, I recall there being some discussion of this, the default 
extent is now a little more than the datalayer. Given the regular 
banding that appears in the difference image, I am inclined to believe 
that this is the cause of the difference. I will be traveling Jul 8 and 
9th with sporadic Internet access, but can dedicate the 10th to more 
digging if it is not too late.

-pete

-- 
====================================
Peter J. Ersts, Project Specialist
American Museum of Natural History
Center for Biodiversity and Conservation
Central Park West at 79th Street
New York, New York 10024
Tel: Home Office (518)-632-4745 or NYC Office (212)-496-3488
Web: http://biodiversityinformatics.amnh.org
Web: http://cbc.amnh.org

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