So In the US, many ways have more then one route designation. For example US 20 in upstate New York, USA is just US 20 basically from Buffalo, New York to about Avon, New York, then it combines with US:NY 5 and both run together on the same way for many miles going east. On the portions that run separate have them tagged (separately) with “ref=US 20” and “ref=US:NY 5”, then when they come togethr, I have them tagged (as suggested on the OSM wiki) us “ref=US 20; US:NY 5”. The separate portions render with “US 20” and “US:NY 5” tags on them, but the portion that runs together does not render any tag. Am I doing something wrong?
No you are doing as has been described. But as far as I know the mapnik renderer can’t handle multiple values seperated with ; so while it’s a good and accepted idea todo it that way it’s not supported.
Any idea if this is something that will change in mapnik? Is this a bug, or simply something that hasn’t been implemented yet?
One possible solution would be to use relations, I’m not sure but it should work (not sure in anyway). This problem is a good example of why relations are needed. You could search on trac to see if someone is working on it, I don’t know myself. But it’s something that everyone knows about but I have seen noone being concerned enough to try to fix it.