[Qgis-developer] QgsRasterLayer::bandStatistics

[Tim Sutton]

Hi

On Wed, Jul 25, 2012 at 7:41 PM, Etienne Tourigny
<etourigny.dev at gmail.com> wrote:
> Hi all,
>
> I had a conversation with Radim about cleaning up the rasterstats
> interface in qgsrasterlayer, he is going to work on this soon as well
> as make some improvements.
>
> Tim - do you have the time to merge your changes to avoid duplication
> and conflicts?
>

I think it is better you make your changes the branch I have the work
in is largely defunct with all the work going on in raster so I will
just pick out any useful bits when I have time.

> Also, I was wondering if any stats-related functions in qgsrasterlayer
> should be removed entirely or kept for backwards-compat for some time
> (and internally get the result from rasterdataprovider)?

Now is the time for radical changes....just document them on the API
breakage wiki page [1]

[1] http://hub.qgis.org/wiki/17/API_changes_for_version_20

Regards

Tim

>
> Etienne
>
> On Mon, Jun 25, 2012 at 5:33 AM, Tim Sutton <lists at linfiniti.com> wrote:
>> Hi
>>
>> On Mon, Jun 25, 2012 at 9:39 AM, Marco Hugentobler
>> <marco.hugentobler at sourcepole.ch> wrote:
>>> Hi
>>>
>>> While fixing the raster issues (in a branch), I'm trying to clean out the
>>> raster layer class. Especially, I'm trying to remove symbology related
>>> elements from the raster layer (like mRedBandName etc.) and have the
>>> symbology only in the renderers .
>>>
>>> Now I'm not sure what to do with the band statistics. QgsRasterLayer stores
>>> and caches QgsRasterBandStats. However I see in the gdal provider that GDAL
>>> caches the statistics as well. So my question is if it is ok to remove the
>>> statistics related members in QgsRasterLayer and go directly to the raster
>>> providers. Or is there a reason to have it on layer level that I missed?
>>>
>>
>> IIRC there is a slow stats gathering implementation in
>> QgsRasterProvider which is virtual and can overloaded by providers
>> that are able to get the stats more efficiently. I have some unmerged
>> code that cleans up the raster stats rendered output which I will
>> commit after you have done your changes, but no I can't think of any
>> reason why the provider should not be the canonical source for stats
>> and the stats calls in the raster layer class removed.
>>
>>
>> By the way I just noticed that the histogram tool in raster properties
>> is not working any more for me.
>>
>> Regards
>>
>> Tim
>>
>>> Regards,
>>> Marco
>>>
>>> --
>>> Dr. Marco Hugentobler
>>> Sourcepole -  Linux & Open Source Solutions
>>> Weberstrasse 5, CH-8004 Zürich, Switzerland
>>> marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
>>> Technical Advisor QGIS Project Steering Committee
>>>
>>> _______________________________________________
>>> Qgis-developer mailing list
>>> Qgis-developer at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
>>
>>
>> --
>> Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
>> ==============================================
>> Please do not email me off-list with technical
>> support questions. Using the lists will gain
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-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
==============================================
Please do not email me off-list with technical
support questions. Using the lists will gain
more exposure for your issues and the knowledge
surrounding your issue will be shared with all.

Visit http://linfiniti.com to find out about:
 * QGIS programming and support services
 * Mapserver and PostGIS based hosting plans
 * FOSS Consulting Services
Skype: timlinux
Irc: timlinux on #qgis at freenode.net
==============================================