[Qgis-developer] Testing new network analyses

[Paolo Cavallini]

Hi Alexander,

Il 14/12/2016 08:08, Alexander Bruy ha scritto:

> 2016-12-13 20:44 GMT+02:00 Paolo Cavallini <cavallini at faunalia.it>:
>> just compiled, testing the new functions, but I cannot get any result,
>> starting from OSM unprojected data. Anyone more lucky?

> I have used RoadGraph plugin several times with OSM data and it worked fine.
> Also I tested Processing algs with projected and not projected OSM data, it
> also worked for me. Maybe your points are placed too far from roads or network
> itself contains gaps? In this case adjusting topology tolerance may help.

I am aware of the issue, I tried increasing tolerance, with no results.
That happened with EPSG:4326; when switching to a metric CRS, it works.
My interpretation is that setting a too high tolerance, easy for degrees
(e.g. 1 degree is huge) makes it impossible to compute the path.
Maybe the user should be warned about this.

>> * the new widget to get coordinates from canvas is supernice, can it be
>> uses for other modules (e.g. r.viewsed, and others from GRASS) as well?
> 
> This widget was added about year ago or even later (can't remember exactly when
> I made it). And of course it can be used in any Processing algorithm.

So better if I go through all the algs and list those who need it in a
ticket?

>> * in case of projected layers, the coords as taken from the canvase
>> should be backprojected to original layer CRS.
> 
> This is known issue and it is also happens for extent selector. There
> are no solution
> at the moment, but we (Victor and me) plan to work on it. Hope this
> will be fixed before
> release. Related ticket https://hub.qgis.org/issues/15680.

oh, I should know about this ;)

>> * several commands are still missing to be on par with GRASS v.net
>> modules: would it be usefult to make a list of missing functionalities?
>> Should I fill tickets not to forget about it?
> 
> Well, I never thought about being on par with GRASS and don't know if this makes
> sense.

I do not see why not, e.g. che chinese postman, etc.

Thanks a lot.

-- 
Paolo Cavallini - www.faunalia.eu
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