Re: [Qgis-user] mapping bus routes

Thu, 07 Oct 2021 14:59:04 -0700

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.


Le 7 oct. 2021 à 17:23, Nicolas Cadieux <njacadieux.git...@gmail.com> a écrit :

 Oups!  Forgot the list…


Le 7 oct. 2021 à 17:23, Nicolas Cadieux <njacadieux.git...@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


Le 7 oct. 2021 à 14:17, Hugh Kelley <hghk...@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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