Brian: Those tiles are indeed no longer available, but you can get the standard toposm tiles (just remove the /usw/ in the URL above). They should cover the west coast as well.

Nice work! I'm glad to see someone mapping the trails in the greater Boston area. I've been working on putting the trails in Wompatuck (on the south shore) on the map, and random trails in other reservations.

Ethan: Thanks for the nice words!

Adam: The street data itself is rendered with Mapnik through a set of custom map styles, though I'm doing a few things that complicate this a bit. The process is described in much more detail in the OSM wiki:

http://wiki.openstreetmap.org/wiki/TopOSM
http://wiki.openstreetmap.org/wiki/TopOSM_howto

Redbeard: Good points.

The altitude color map was really mostly an experiment and I may indeed adjust the colors in the future.

I wasn't planning on using USGS DLG data - that's where OpenStreetMap comes in. I don't think there's a lot of (relevant) information in the DLG files that isn't in OpenStreetMap. And, if there is, I'd rather see it imported or otherwise added to OSM.

http://wiki.openstreetmap.org/wiki/TopOSM#Map_legend

It seems like the thing for me to do is to post the script along with a description of what it does and doesn't do. For now, the TopOSM wiki page on openstreetmap.org will probably be the place to put it.

As for those other scripts suggested above: I've looked at these before, and they're probably good for reference when hacking Mapnik style files. They will list every rule in every style for every data source, rather than the entities that most humans will consider for inclusion on a map key, however, so I think they'd have to be pretty heavily modified to be useful for something like this.

Colin: Your approach of creating a "fake" map and render it is interesting. I actually considered that too, but it seemed like maintenance would be an issue. Especially if one, like me, wants it customized per zoom level.

Thanks both of you!

Colin: Sure - if there is interest, I'll definitely release the source. It's a bit of a hack, but it's not too terrible. :) Although, I think I saw something on one of the mailing lists recently about someone just implementing the same type of thing for the main mapnik layer (and the "Map key" on the OSM website was indeed recently updated).

Thanks for the compliments! I'm glad you like it.

I guess estimating elevation from GPS tracks could work to some degree in densely populated (and GPSed) areas, but overall I think there are few areas where it would be better than even SRTM. It might work for detecting and labeling steep inclines along roads, e.g. for a cycle map (as you mention), though. Could be a fun project.

Thanks!

Well... adding it as an OSM layer would be nice. :) Unfortunately, the elevation data isn't available for all countries, or even all US states. In fact, there are probably places in the world where this type of data just doesn't exist. This map has much higher detail in the topography than e.g. SRTM (which *is* available for the entire globe).

Currently TopOSM is Massachusetts only, but if I find similar data for other areas, I might render those areas as well.

Ah, of course... you're right. From working with both TIGER and MassGIS road data in the past, it appears to me that either the latter is based on TIGER or they just share many of the same issues. Nevertheless, you're probably right the MassGIS is generally higher quality.

Either way, Wompy could certainly use some work... :)