[Qgis-developer] Quick fixes and error communication for ftools

[Matthias Kuhn]

Hi Marco

Good to have your feedback, you probably know the problem best.

On 11/24/2015 09:28 AM, Marco Hugentobler wrote:
> Hi
>
> >ad issue 1: update fTools to warn users when some features cause problems
> >ad issue 2: quick fix fTools to convert geometry collections to
> single geometry types
>
> A function that takes a geometry type and extracts the longest line /
> the largest polygon / the first point from the geometry collection
> should be straightforward to do.

Is there no requirement for multi types?
Based on what indicator should be chosen what to extract? Try polygons
first, if there are none try lines, if there are none take points?

>
> >These fixes/updates would be made available as fTools updates via the
> plugin installer asap
>
> If the fix does not take too long, we probably don't need a warning at
> all.

How much effort (in time) do you think is required to implement this fix?

Regards,
Matthias

>  
> Regards,
> Marco
>
> On 23.11.2015 21:35, Anita Graser wrote:
>> Hi,
>>
>> If you are following the psc list, you've probably seen the thread
>> discussing current shortcomings of ftools
>> (http://lists.osgeo.org/pipermail/qgis-psc/2015-November/003623.html)
>>
>> In short, the key issues are:
>> 1. When ftools encounter issues with certain features, warning
>> messages get written to the log but this is largely hidden from users
>> since they would actively have to actively monitor the log. The
>> problematic features are then missing from the results but this is
>> not always obvious. 
>> 2. The above issue is more common now (since 2.10) since underlying
>> libraries more often (and correctly so) produce geometry collections
>> as outputs. These geometry collections are not handled well by the
>> current ftools code which is much older.
>>
>> To address these issues, the following suggestions have been made so
>> far: 
>> ad issue 1: update fTools to warn users when some features cause problems
>> ad issue 2: quick fix fTools to convert geometry collections to
>> single geometry types
>>
>> For the warnings, there's already a first PR
>> draft https://github.com/qgis/QGIS/pull/2432 which needs to be
>> fleshed out. 
>>
>> These fixes/updates would be made available as fTools updates via the
>> plugin installer asap. 
>>
>> If you have ideas how to handle this efficiently or have already
>> implemented code that addresses similar issues, let us know. 
>>
>> It would be good to have a quick discussion in order to be able to
>> provide improvements fast.
>>
>> Best wishes,
>> Anita
>>
>>
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>
>
> -- 
> 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 
>
>
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-- 
Matthias Kuhn
OPENGIS.ch - https://www.opengis.ch
Spatial • (Q)GIS • PostGIS • Open Source

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