TopOSM US - A Progress update

Posted by Ahlzen on 15 December 2009 in English (English)

While work on TopOSM ( has been somewhat slow recently for various reasons, there has been some important progress that I wanted to share.

Currently I'm attempting to create a TopOSM-style map for the entire United States. While that may seem almost trivial, since two states are already finished, I can assure you that it is not.

The first step, which is, hopefully, complete, has been to gather all of the required data. In addition to OSM data for most map features, I've been using the USGS National Elevation Dataset to generate hillshading and contour lines. I recently received the approximately 600 GB large 1 and 1/3 arc-second NED data for the entire United States, plus several other interesting datasets. Additionally, I have received the National Hydrography Dataset - a detailed dataset containing rivers, lakes, wetlands and other hydrographic features - for the entire United States. The latter is (slowly) being imported into OSM, by the way. I really owe the helpful people at the USGS a big thanks for providing me with these!

The fact that these data sets are very large make them at least an order of magnitude more difficult to work with than what I've previously encountered. Things that should work just don't. There are countless cases where large data files have to be split and processed sequentially because of memory limitations, disk space or just plain bugs or limitations in the software. Once everything works, the project will require a massive amount of CPU time and disk space to render. That's a later problem, however, and it's a job that can be distributed if necessary.

At this point, I have an almost working set of scripts to process all of these different data sources and finally render map tiles. There are plenty of bugs left to work out and many needed improvements, but at least it's moving forward. I'll post further updates and examples here as the work progresses.

Comment from Ethan O'Connor on 15 December 2009 at 06:06

Great news! Just wanted to leave a note of encouragement -- getting data into OSM is really the easy part; building visualizations and other access methods is a whole other story and your work in that direction is inspiring and beautiful.


Comment from Adam Geitgey on 15 December 2009 at 06:19

Your maps look pretty much fantastic! What are you using to generate your map tiles for the street data? I'd love to do something like this for Baja California.

Comment from Ahlzen on 15 December 2009 at 13:16

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:

Comment from Adam Killian on 15 December 2009 at 14:01

I had not heard of TopOSM before today, I just wanted to express my amazement. Your renderings are absolutely beautiful!

Comment from Jean-Marc Liotier on 15 December 2009 at 17:47

Your announcement made me discover TopOSM and I'm in awe of its beauty. With the CORINE land cover imports going on in Europe, it is going to be magnificent there !

Comment from Adam Geitgey on 15 December 2009 at 21:21


I was just hoping for a quick summary of what you did, but your wiki page goes into amazing detail and is very well written and impressively put together with great diagrams.


Comment from katze_sonne on 15 December 2009 at 23:07


Even when I can't use it (I am living in Europe ^^), I must say: I it amazing! The mapstyle is just gorgeous! I really wonder why noone else could do this stuff? Therefore it MUST be a LOT of work and I must really say: *thumbs up*!!!
The map just looks like... A real map, a commercial one! When I had a quick look over it there were no render errors (I couldn't find any) :-) You have done really well also in the way how the zoom level settings are (different colours (colour = British English spelling of "color" - that's the way we learn it in Germany ^^ Just that you don't think it is a spelling mistake :-P )of streets (higher contrast) and many other ideas you used to design a really well made map - even some commercial maps are not made that well - I just couldn't find any bad aspects about it :-D )...

YOU have shown all, in my opinion, *how* a good and well considered map must look like! I really would like to see this also for Europe! I know, you don't even have the USA done (and I don't know how it looks about the used data sets - are they all available for Europe as well? I don't know much about this...) but with your superb wiki pages I hope other users (with experience; who know more about these things than "normal, simple mappers" like me) will help you and are being encouraged to do this for Europe, too.

Thank you a lot for all your work and time you put into this! I think, you deserved A LOT of respect!

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