[Qgis-developer] min/max for rasters

Radim Blazek radim.blazek at gmail.com
Fri Dec 13 09:18:33 PST 2013

On Fri, Dec 13, 2013 at 9:55 AM, Paolo Cavallini <cavallini at faunalia.it> wrote:
> Hash: SHA1
> Hi all.
> The default for raster rendering is to cut values at 2-98%. This is
> inappropriate in many cases, and confusing for users. Is that OK if I
> change the default to min/max?

Min/max is inappropriate in many other cases. It is quite common to
get data with few outliers. The result in such cases with min/max is
black rectangle which is very frustrating and that was the case with

I believe that it is better to get inappropriately rendered picture
than black rectangle. I understand however that it may be problem that
user does not notice that the cut was applied.

If we find 2-98% as bad as bad min/max we should invent something
better, not just switch from one bad solution to another one. We can
discuss for example the range (2-98%,1-99%,0.1-99.9%...) and different
situations (data types, number of bands).

Can you describe some examples where 2-98% is a problem (data type,
number of bands, map content, features/phenomena represented by those
2+2%,...) so that we can think about it better?


> All the best.
> - --
> Paolo Cavallini - www.faunalia.eu
> QGIS & PostGIS courses: http://www.faunalia.eu/training.html
> Version: GnuPG v1.4.15 (GNU/Linux)
> Comment: Using GnuPG with Icedove - http://www.enigmail.net/
> B10An2qhIuojWaPsCXnJmhb7stUbvQ6c
> =I+Xp
> _______________________________________________
> Qgis-developer mailing list
> Qgis-developer at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-developer

More information about the Qgis-developer mailing list