[Tagging] Named junctions

[Andrew Errington]

Surely this is a rendering problem?

In other words, if there are many named traffic lights within a
certain distance of each other then only one symbol/name/whatever
should be rendered?  If the traffic lights are all tagged the same
then it ought to be even easier.

Adding an area with a tag is just a band-aid, plus it's a lot of work
for mappers.  If we can distil a rule from the data then the computer
can do all the work for us.  Unfortunately, writing software is also
hard, and we have to hope somebody else will do it, but having a clear
explanation of the task is a great help.

It could be something like "when a named traffic light node is found,
add it to a group with that name.  When it's time to label the map,
decide how much space is available for the label, depending on the
zoom level.  At low zoom, draw a single traffic light icon, centred on
the average of the nodes in the group.  At medium zoom, draw a single
icon and a label.  At high zoom, draw an icon for each node, and a
single label in the centre".  This would also work for single named
traffic lights (they are in a group of one).  Single unnamed traffic
lights would work if they are alone (i.e. on a simple junction).
Unnamed traffic lights close together would not work (because they can
not be grouped by name), but there could be a pre-processing step that
makes a group based on the nodes being close together, say within 10m
of each other.

A relation would also be a good solution.  Group the traffic lights
together and add them to a relation with the junction name.  Then
render icons and/or labels for each relation, based on the zoom level.
This would make the rendering code easier, but would be a lot of work
for mappers.

Andrew

On 09/11/2015, tomoya muramoto <muramototomoya at gmail.com> wrote:
> Hi Javbw, I want to confirm your point.
>
> *You want to establish a new tag such as traffic_signals_area to solve
> multiple signals rendering.
> *Opinions on the new tag are welcome from Japanese/Asian community because
> rendering of traffic signal and its name is very important for (car)
> navigation in Japan/Asia.
>
> You showed another issue such as dual labels or default map localization,
> but I want to focus on the above issue at this time.
>
> I will post a mail to Japanese ML after some document translation finished
> such as traffic_signals_area.
>
> --
> I like Mapion too. But Mapion is not perfect.
>
> At first, check Yahoo map.
> http://maps.loco.yahoo.co.jp/maps?type=scroll&datum=wgs&mode=map&pointer=off&lat=35.4573089010882&lon=139.619295364418&z=19
> You will see an unnamed traffic signal just north of Tobe (戸部) station.
>
> However Mapion doesn't show it.
> http://www.mapion.co.jp/m2/35.45725737865473,139.61930034601284,19
> And Google map doesn't show it.
>
> And you will notice multiple traffic signals rendering on Mapion just east
> of that signal. Nothing is perfect. But at least we can make OSM better.
>
> muramoto
>
> 2015-11-09 20:28 GMT+09:00 Michał Brzozowski <www.haxor at gmail.com>:
>
>> On Mon, Nov 9, 2015 at 11:59 AM, johnw <johnw at mac.com> wrote:
>>
>> > Google Maps is actually two different sets of data: Google’s and a
>> Japanese
>> > GIS company, Zenrin. They have basically surveyed all of Japan building
>> by
>> > building, and everything is drawn area based (because the roads in
>> > Japan
>> can
>> > be such weird shapes and always change width suddenly).
>>
>> Frankly I don't find their road system to be that different to
>> necessitate areal representation, I guess it's more of a tradition
>> thing. But if you don't know, there is area:highway tagging scheme
>> developed by Marek Kleciak that allows to represent roads as areas, as
>> an extension to their linear representation. Note this is distinct
>> from area=yes highways that simply don't have any meaningful axis. If
>> there are resources available, people of Polish community (marimil)
>> could help set up a visualization layer for it.
>>
>> Michał
>>
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>