[Talk-us] Shaped highway shields - trying to revive

[Kevin Kenny]

I'm trying to get them involved, but tile-serving rejects my mails. There's
someone on the server admin team looking into it, but no luck yet. There
may have been further progress today, but I've been out hiking and only
just got back to my email. I'm not yet to the bottom of my inbox.

On Fri, Aug 24, 2018, 2:27 PM Martijn van Exel <m at rtijn.org> wrote:

> Agreed. I think it's really nice to have active thinking and work around
> this. The key is to get the rendering stack people involved. Perhaps Paul
> Norman can function as a liaison?
>
> Martijn
>
> Sent from my iPhone
>
> On Aug 24, 2018, at 12:06, Evin Fairchild <evindfair at gmail.com> wrote:
>
> Really glad to see that someone is reviving this and actually taking the
> step to get it rendered. Frankly, I never understood why Phil didn't do
> this in the first place. I even mentioned this to him at the time (can't
> remember his response though).
>
> -Evin (compdude)
>
> On Wed, Aug 22, 2018, 2:21 PM Kevin Kenny <kevin.b.kenny at gmail.com> wrote:
>
>> (I apologize in advance to the tile-serving community if this message
>> is inappropriate. I see that traffic on that list is largely limited
>> to highly specific technical discussions, but couldn't see a more
>> appropriate forum.)
>>
>> For several years now, I've been using the support code for shaped
>> shields in OSM, originally developed by Phil! Gold and Richard Weait,
>> to render North American-style maps. A typical example can be found at
>> https://kbk.is-a-geek.net/catskills/test4.html?la=41.4143&lo=-74.4233&z=14
>> In that view, you can see distinct shields for Interstate, US, New
>> York, and county routes, and at least one concurrence (New York 17M
>> aligned with US 6). Incidentally, Phil's is the only renderer that
>> I've seen that can make sense of cases like West Virginia's bizarre
>> double route numbers, as seen in
>> https://kbk.is-a-geek.net/catskills/test4.html?la=41.4143&lo=-74.4233&z=14
>> .
>>
>> The visual distinction among highway shields is really necessary in
>> North America, where there are so many different route networks
>> overlaid.
>>
>> In the course of working with the code, I've made a number of changes
>> and become seriously out of sync with the main development line, which
>> appears to be moribund. (Phil! and Richard have not answered recent
>> queries; I suspect that I have obsolete contact information, but the
>> messages also have not been returned undelivered.)
>>
>> Accordingly, I've (quite reluctantly) created my own repository -
>> https://github.com/kennykb/osm-shields - with material from the
>> project. The shield templates to be found there are mostly those of
>> Phil! (I added only a handful), but the code to manage shields is
>> almost entirely new. Some significant changes are:
>>
>> The list of shields to be rendered is obtained from the database
>> itself, rather than being predetermined by a configuration file for
>> each network. This has the disadvantage that refs that are known to be
>> problematic may be rendered (but in most cases they ought to be
>> unsigned_ref). On the other hand, it has the distinct advantage that
>> as mappers continue to create the route relations, the corresponding
>> shields appear virtually automatically.
>>
>> The composition of shield clusters, rather than being handled by a
>> stored procedure in the database, is done using a GroupSymbolizer in
>> Mapnik. I suspect, given the dearth of discussion that I find in a
>> Google query, that I'm the first user to attempt to use
>> GroupSymbolizer with actual open-ended shield clusters, and therefore
>> that I've trodden new ground in the path from database to renderer. I
>> encourage developers who are interested in the GroupSymbolizer to read
>> at least
>> https://github.com/kennykb/osm-shields/wiki/Using-the-GroupSymbolizer
>> - it has a number of tricks to structure the results in a way that the
>> GroupSymbolizer can consume and that renders well. The disadvantage to
>> using the GroupSymbolizer is that Phil!'s shield clusters were rather
>> more attractive visually, since they were aligned to lie in the
>> direction of a way. The advantage is that the current approach can run
>> on an unpatched Mapnik, as opposed to Phil!'s original, which requires
>> at least patching Mapnik to use a read/write connection to the
>> database.
>>
>> Managing, reliably, the association between ways and the routes in
>> which they participate requires a couple of database tables that a
>> stock osm2pgsql does not produce. I would very much appreciate any
>> commentary from developers of osm2pgsql and Mapnik, particularly,
>> about the issues discussed in
>>
>> https://github.com/kennykb/osm-shields/wiki/Maintaining-the-association-between-ways-and-routes
>> What I'm currently doing works well for my own use, which is driven by
>> daily updates to extracts at Geofabrik, but will obviously not scale
>> to a whole planet and minutely updates.
>>
>> Finally, I'd really like to invite anyone with the necessary SVG
>> skills to contribute shield graphics for the missing networks. If
>> you're also a programmer and want to take a whack at the rest of the
>> procedure in
>> https://github.com/kennykb/osm-shields/wiki/Adding-new-networks,
>> and give me a pull request or ask for help, that would be even better,
>> but even the artwork would be a time-saver.
>>
>> If you've got this far in reading, thanks! I know this was a long
>> message, and I hope that I've not wasted too much of anyone's time.
>>
>> _______________________________________________
>> Talk-us mailing list
>> Talk-us at openstreetmap.org
>> https://lists.openstreetmap.org/listinfo/talk-us
>>
> _______________________________________________
> Talk-us mailing list
> Talk-us at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-us
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-us/attachments/20180824/a8c7fd85/attachment.html>