[Qgis-user] mapping bus routes

[Hugh Kelley]

Thank you Nicolas I will give that yutube video a look.

I have historically handled the orientation problem by checking azimuths
but actually fixing the linework may save me some time in some cases so I
think there's good potential there.


David you're exactly right about that aspect of the problem, its not a
simple thing. Add to that a preference to have a route that eventually
turns right offset to the right of an overlapping route that continues
straight and its even more complicated. Its also sometimes difficult to
decide how to handle stop points as well.

Would be a nice plugin to put together to convert real routes into stylized
routes but I think that would be a fairly demanding long term project on my
end at least.

On Thu, Oct 7, 2021, 5:53 PM David Strip <qgis-user at stripfamily.net> wrote:

> For a transit map, it seems the offset would not be constant. Consider two
> bus routes that overlap along a single street in their routes. On that
> street, the two lines typically would be offset to opposite sides of the
> line representing the street. On the rest of the route, however, the route
> would be shown as lying directly over the centerline, not offset to either
> side. Life gets even more complicated when multiple routes overlap with
> different numbers of other routes at various points on the map.  Or at
> least that's what I've typically seen on transit maps.
>
> On 10/7/2021 3:30 PM, Nicolas Cadieux wrote:
>
> Hi,
> You can also trim the lines in the symbology (at least in QGIS 3.20) as
> well as giving it an offset.  That will insure that intersection are not
> overlapping in the offset.
>
> Nicolas Cadieux
> https://gitlab.com/njacadieux
>
> Le 7 oct. 2021 à 17:23, Nicolas Cadieux <njacadieux.gitlab at gmail.com>
> <njacadieux.gitlab at gmail.com> a écrit :
>
>  Oups!  Forgot the list…
>
> Nicolas Cadieux
> https://gitlab.com/njacadieux
>
> Le 7 oct. 2021 à 17:23, Nicolas Cadieux <njacadieux.gitlab at gmail.com>
> <njacadieux.gitlab at gmail.com> a écrit :
>
>  Hi,
> You can automatically draw an offset by adding a offset in the symbology.
> Things get more complicated when line vectorization changes directions as
> the offset flips side depending on, for example, if the line is drawn from
> A to B or B to A.
>
> In the QGIS models, https://plugins.qgis.org/, go to models then Fix
> Directional Network models 1,2 and 3.  That will help you find problems
> (like disconnected lines) but also identify all the lines that are flipped.
> You can then flip them manually or figure out an algorithm to do it
> automatically.
>
> You will also find a boring YouTube video on my YouTube channel.
> https://youtu.be/v61PafSByvM
>
> Nicolas Cadieux
> https://gitlab.com/njacadieux
>
> Le 7 oct. 2021 à 14:17, Hugh Kelley <hghklly at gmail.com>
> <hghklly at gmail.com> a écrit :
>
> 
> Hi all,
>
> I'm wondering if anyone has any good tricks for mapping bus routes. The
> key problem is defining how to offset lines where the routes overlap.
>
> I've handled this by chopping up the lines and offsetting in postgis
> according to some st_dwithins and st_intersections but wanted to see if
> there is anything in the wide world of QGIS that I'm not aware of.
>
> My understanding is that it's a fairly significant challenge to do a great
> job with it. A company called transitapp had an interesting blog post about
> it a while ago.
> https://archive.transitapp.com/transit-maps-apple-vs-google-vs-us-cb3d7cd2c362#.e9kcryzg1
>
>
> Hugh
>
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