[Talk-us] Highway Shield Rendering

stevea steveaOSM at softworkers.com
Mon Apr 2 22:36:23 BST 2012

>Shields are supposed to start rendering at zoom 10, but they're not....

>  > Yes, 12, 13 and up to 14 work, but 15 and above just display pink tiles.

>It depends on where you are looking.  If you're getting a lot of pink

Good explanations, thank you.

>I'm deliberately leaving county routes for a second phase and focusing on
>state routes for the moment.  (New Jersey is an exception, but it was an
>experiment and I don't actually believe we're using the proper shields for
>all of its counties.)

Starting with a "more difficult" example like New Jersey is smart, as 
other, less complicated states just inherit already-complex rules and 
"simply work."

>  > And oddly, in the San Diego area, "CA 209" and "CA 75" (Point Loma
>>  and Coronado, respectively) don't render with your newer shields,
>>  but the old style Mapnik shields.
>It looks like there aren't route relations for those routes yet, so the
>rendering falls back to the old shield style for them.

Which makes a "mapnik/standard vs. aperiodic.shields" comparison very 
direct, now that we know this.  Knowing so will allow edits to move 
towards the "more correct" method so your render rules work.

>  > Also, there are some toll ways in Orange County (California, e.g. CA
>>  73, CA 241) which don't render specifically as toll, but as there is
>>  no distinct shield in California to distinguish toll roads, I'm not
>>  sure this is a defect in your algorithm or renderings -- the regular
>>  state route shield is displayed, apparently correctly.
>Do toll roads get any difference in signage, like a banner above or below
>the shield?  If so, then we just need to make images that match and get
>routes that identify them.  (Right now that would probably be with a
>network of US:CA:Toll, but see NE2's and my emails about Florida toll

There is no specific shield in California which specifies a toll road 
(to the best of my knowledge).  On legally-defined Interstates which 
are toll (like I-80/I-90 sections of the Ohio Turnpike) I have seen 
SOME (printed, non-OSM) maps shield these not blue, but a 
light-medium green, though the shields on the road itself remain the 
standard red-white-blue for Interstates.  I have also seen that 
light-medium green color on printed, non-OSM maps for the California 
highways which are toll (instead of blue, usually), but that can get 
confusing, as frequently Business Routes are printed with 
light-medium green shields (and a very-tiny-type "Business" at the 
top).  In California, the shield (said to be a "miner's spade" 
reminiscent of old '49er gold digging) for freeways and state routes, 
whether truly a "free way" or a toll road, is dark-medium green in 
reality.  My point is that some printed, non-OSM maps do make a color 
distinction on state routes in California which are toll.  They have 
to be careful not to confuse these with Business Routes, either by 
color or by printing a hard-to-see "Business" distinctly on the 

>(Business Routes) might not show up.  Based on previous discussions 
>on this list, we've
>chosen to look for the business designation (as well as others) in the
>network tag on the route relation.  A lot of relations have the route
>modifier in the ref tag, though (so they might be network=US:US,
>ref=5 Business instead of network=US:US:Business, ref=5), so they don't get
>rendered at the moment.  (And on top of that, there are slightly different
>signs for spur and loop business Interstates, so I ended up looking for
>networks like US:I:Business:Loop and US:I:Downtown:Spur even though no
>one's actually doing that yet.)
>There are some business routes that our rendering understands here:

It seems you are going to have a relatively complex parse for 
business routes, above and beyond how you get that/those particular 
shield/s to render in Maryland.  In other words, the bad news is you 
still have much work to do.  But the good news:  even though they are 
quite tiny, I actually CAN read "Business" and "Maryland" on those 
displayed shields, and even distinguish between them without zooming 
out (notwithstanding the shape of the shield itself).  Nice job!


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