[Qgis-psc] GEOS discussions

[Tim Sutton]

Hi

> On 25 May 2015, at 12:18, Sandro Santilli <strk at keybit.net> wrote:
> 
> Hi Tim, all.
> I went re-reading the threads and I think the next step here is on
> Sandro Mani to take.

Thanks for taking a look!

> 
> For the M values support he made a PR which I'm esitant to merge due to
> its effect of growing every coordinate used by GEOS by 30%. A compile-time
> define to enable/disable it would make it easily acceptable.


I guess the issue with this is that we will need to ask upstream packages to enable this flag for different distros in order for us to be able to use the geometry checking tools in QGIS….which means that there will be anyway a 30% overhead added…..or we need to bundle in our own copy of the geo lib into the QGIS source tree with the correct flags enabled which also isn’t great. Is there anyway to make it a run time switch rather than a compile time switch? Seems like that would solve a lot of issues.

> 
> For the PrecisionModel discussion there's no PR yet.
> 
> I'll be busy till the end of October so won't be able to take more work
> to look at those issues myself.


Ok thanks!

Regards

Tim


> 
> --strk;
> 
> 
> On Sun, May 24, 2015 at 12:10:05AM +0200, Tim Sutton wrote:
>> Hi Sandro
>> 
>> Greetings and how are you? During the hackfest we just had in Denmark, the fine folks at Sourcepole presented some really awesome new tools for QGIS for checking and repairing geometry issues. Having these tools added to QGIS master will be a huge feather in our cap. However they have two blocking issues preventing the merge of this new tool - both relating to QGIS (see below Pirmin’s details of the outstanding issues). I am wondering if There is something we can do to help you get PrecisionModel and M value support working nicely in GEOS (and in default compilation flags) so that we can pave the way to getting the geometry checker / fixer tool incorporated? PSC would you be agreeable to spending some of our funds to support Sandro to put in the time needed to resolve these issues?
>> 
>> Regards
>> 
>> Tim
>> 
>> 
>>> On 22 May 2015, at 08:22, Pirmin Kalberer <pka at sourcepole.ch> wrote:
>>> 
>>> Hi Tim,
>>> 
>>> There are two important pending points:
>>> 
>>> 1. C API exposition of the PrecisionModel
>>> 
>>> Needed for the new QGIS geometry checker.
>>> 
>>> This was the last discussion:
>>> http://lists.osgeo.org/pipermail/geos-devel/2015-January/007080.html
>>> 
>>> 
>>> 2. Support for M values in GEOS
>>> 
>>> For processing geometries with M values with the new QGIS geometry model, we 
>>> need also support for M values in GEOS. Documentation says that GEOS supports 
>>> M values, but the this is not the case.
>>> Sandro's pull request:
>>> https://github.com/libgeos/libgeos/pull/45
>>> 
>>> Regards
>>> Pirmin
>>> 
>>> -- 
>>> Pirmin Kalberer            @PirminKalberer
>>> Sourcepole - Linux & Open Source Solutions
>>> Weberstrasse 5, 8004 Zürich,   Switzerland
>>> Tel: 044 440 77 11   Direkt: 044 51 567 77
>>> pka at sourcepole.ch http://www.sourcepole.ch
>>> 
>> 
>> —
>> 
>> 
>> 
>> 
>> 
>> Tim Sutton
>> 
>> Visit http://kartoza.com <http://kartoza.com/> to find out about open source:
>> 
>> * Desktop GIS programming services
>> * Geospatial web development
>> * GIS Training
>> * Consulting Services
>> 
>> Skype: timlinux Irc: timlinux on #qgis at freenode.net
>> Tim is a member of the QGIS Project Steering Committee
>> 
>> Kartoza is a merger between Linfiniti and Afrispatial

—





Tim Sutton

Visit http://kartoza.com <http://kartoza.com/> to find out about open source:

* Desktop GIS programming services
* Geospatial web development
* GIS Training
* Consulting Services

Skype: timlinux Irc: timlinux on #qgis at freenode.net
Tim is a member of the QGIS Project Steering Committee

Kartoza is a merger between Linfiniti and Afrispatial

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