[Qgis-developer] Raster resampler branch

[Tim Sutton]

Hi Marco

On Fri, Apr 6, 2012 at 7:22 PM, Marco Hugentobler
<marco.hugentobler at sourcepole.ch> wrote:
> Hi Tim
>
> Thanks for looking at the branch. I agree that the ui should be improved and
> I appreciate help in this regard. Hope we can work on the ui design (and on
> other issues in the raster branch) in Lyon.
>

Yes that will be great.

>
>>- Its also not obvious what the threshold is where the large kicks in
>>over the small scale resampling approach
>
> The treshold is the zoom level where one screen pixel equals a source raster
> pixel (the zoom level applied with the 'zoom to best resolution' function).
>
>

Yes I understood that - I meant to say 'its not obvious to the average user'

>> - the number spin box - its not obvious what it is for
>
>
> It is the maximum oversampling ration for the average resampler (afaik UMN
> has the same parameter). Depending on the zoom-level, the average resampler
> pulls data in higher resolution than on screen (depending on raster source
> resolution). A value of 2 e.g. ensures the resampler does not pull more than
> 4 times the screen resolution when zooming out.
>

Ah ok good to know - also something we should make understandable for
users and probably hide away in an advanced section.

Thanks!

Tim

>
>
> Regards,
> Marco
>
>
>
>
> On 06.04.2012 00:45, Tim Sutton wrote:
>>
>> Hi Marco
>>
>> On Wed, Apr 4, 2012 at 4:23 PM, Marco Hugentobler
>> <marco.hugentobler at sourcepole.ch>  wrote:
>>>
>>> Hi devs / power users
>>>
>>> Today, I've uploaded a lot of changes to the raster_resampler branch on
>>> github ( https://github.com/qgis/Quantum-GIS/tree/raster_resampler ).
>>> Compared to the previous version (which already provided resampling
>>> capabilities and code refactoring into raster renderer classes), there is
>>> now quite a lot of GUI refactoring. The style tab of the raster
>>> properties
>>> dialog now contains an embedded renderer dialog for the current renderer
>>> type (similar to how it is in the vector props. dialog). Furthermore, it
>>> is
>>> now possible to dynamically add new raster renderers and corresponding
>>> dialogs.
>>>
>>> I'm interested in feedback and like to discuss the raster changes also in
>>> Lyon. The user interface could be improved for sure and there will most
>>> likely be some new bugs. If you find one, please fill a ticket and assign
>>> it
>>> to me.
>>> Note that the branch also has a number of advantages:
>>> - Raster look much nicer with resampling
>>> - The raster banding issue when printing transparent layers is solved
>>> - Fixes problem with raster transparency band that was not saved in
>>> master
>>> - Efficiency has been improved for some common cases (e.g. faster lookup
>>> when rendering paletted rasters)
>>> - It is now easier to make changes in the raster layer class since most
>>> of
>>> the symbology and rendering related code is moved out of QgsRasterLayer.
>>>
>> I've done a bit of testing with this it seems to be working well. Some
>> comments:
>>
>> - the user interface needs to be sorted out for the symbology tab -
>> the load button sits too far from the min/max controls. Ultimatelye I
>> think we need to completely rethink the style ui - maybe using a
>> property list would be better....
>> - Some of the settings are not intuitive - its not obvious how you
>> return to the default behaviour for the large/small scale combos
>> - Its also not obvious what the threshold is where the large kicks in
>> over the small scale resampling approach
>> - the number spin box - its not obvious what it is for
>>
>> Other than those issues it was working well for me though I still need
>> to test it with some of my larger datasets.
>>
>>> The next thing I'm planning to make in the branch is to add project file
>>> transformations. The new xml format is different than the old one, so old
>>> symbology settings won't load properly from project file right now.
>>
>> Yes that would be good!
>>
>> Regards
>>
>> Tim
>>
>>> Regards,
>>> Marco
>>>
>>> --
>>> Dr. Marco Hugentobler
>>> Sourcepole -  Linux&    Open Source Solutions
>>> Churerstrasse 22, CH-8808 Pfäffikon SZ, 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
>>
>>
>>
>
>
> --
> Dr. Marco Hugentobler
> Sourcepole -  Linux&  Open Source Solutions
> Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
> marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
> Technical Advisor QGIS Project Steering Committee
>



-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
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