The TIGER versus OpenStreetMap Battle Grid, improved!

I reposted this story on my OpenStreetMap Diary. I think the diaries are a great asset to the OpenStreetMap community and they are not used as much as they should. I will try and post more of my OpenStreetMap-related stories there (as well).

If you follow the blog at, you will have heard about the Battle Grid. It is a map that shows you where recent TIGER data is different from OpenStreetMap data. Because TIGER has improved a lot over the years, and has kept up reasonably well with new road construction, a big difference between TIGER and OSM tells us that OSM likely needs some love. Here is how the battle grid looked until today:


Cells with a lot of difference between TIGER and OSM are brighter, and as a simple way of prioritizing the cleanup and update work, I colored the cells that are within a Census CDP orange, and the rest green.

As of today the Battle Grid will look like this, instead:


The brightest cells are still the most different. What is new is a color spectrum ranging from green to red, indicating how many people drive in and through each cell. This is based on Telenav logs. Because lots of people use Telenav apps such as Scout every day, it should be a fair representation of interestingness.

Let me show you a few examples of bright Battle Grid cells to whet your appetites.

Here’s a bright red cell in Greenville, NC:


Look at this! Missing subdivisions, and poorly aligned streets. A mess!


If I weren’t writing this blog post I’d be fixing this…

The green cells are usually no less, ehm, interesting. Here’s one in Saint Louis, MO:


I guess someone had a plan for this area, and the someone with more money / power came along with a different plan, and nobody ever told Census:


What I generally find is that the bright cells on the fringes of urban areas are most gratifying. These usually represent either poorly aligned OSM data, unmapped new subdivisions, or a combo of both.

Speaking of fringes, I think Atlanta has a great visual Battle Grid story:Image

The city itself is well mapped with very few bright cells. (And whatever there was is mostly black, so people have already marked them as done.) The fringes still show a lot of, well, let’s call it mapping potential!

What are your favorite Battle Grid finds? Share them below!

New MapRoulette challenge: Lane Counts

MapRoulette is overdue for a new challenge, and we have one that should keep us busy for a while: adding numbers of lanes to the main roads in N-America. This information would be great to have for advanced visualization and transportation analysis purposes. And a lot of it is already there, so let’s just make it complete.

The challenge works as follows: You fire up MapRoulette as usual by going to You are presented with one OSM way somewhere in North America that does not have a lanes=* tag. (We only care about secondary and higher to keep things useful and manageable, and we’re starting with the motorways and moving down, so you should see only motorways at first.)

Screen Shot 2013-04-06 at 1.26.55 PM

If you want to fix this road, click on ‘Edit in JOSM’ and wait for the way to load in JOSM. Make sure you have JOSM running, otherwise the button won’t work.

Screen Shot 2013-04-06 at 1.30.26 PM

To actually see the number of lanes of this road, you may need to zoom in a little.

Screen Shot 2013-04-06 at 1.32.36 PM

Aha! This road has two lanes. So we go ahead and add that as a tag to the road. Hit Alt-A (Option-A on a Mac) or click ‘Add’ in the Properties pane:

And enter the information in the tag dialog:

Screen Shot 2013-04-06 at 1.49.03 PM

Click OK.

Now upload your change, adding a brief changeset comment in which you should mention you used MapRoulette – for example by adding #maproulette:

Then, return to MapRoulette and indicate that you have fixed the problem!


Not all cases are this simple. There’s a few things you need to look out for.

In some cases where the amount of data to load into JOSM would become too big, JOSM will only load the actual way that requires your attention, not the data for the entire area.

Here’s an example:

Screen Shot 2013-04-06 at 2.11.59 PM

If you zoom in and deselect the road, you can see that this road is marked as oneway.

Screen Shot 2013-04-06 at 2.16.46 PM

Because this looks like a dual carriageway road from the aerial imagery, there is probably another OSM way representing the other side of this road. If unsure, confirm by loading more data.

In these cases where only the actual way is loaded, you should also avoid moving or deleting nodes from the way, as these nodes may be shared with other ways you cannot see. Before you make any such changes, load more data.

Also, only enter the number of travel lanes and do not include merge lanes. Here’s an example:


Screen Shot 2013-04-11 at 3.58.11 PMThe right lane is a merge lane, and does not count towards the main road lane count. So in this case the way would get lanes=3. You can see that it’s a merge lane by looking at the context (pan around and you will see the ramp) as well as by the difference in lane markings.



OpenStreetMap US Virtual Mappy Hour

The new OpenStreetMap US Chapter board has been using Google+ Hangouts for meetings, and it has been serving us well. Hangouts are like conference calls, but you can see each other and that is a huge advantage over just talking on the phone.

Google offers a more public variation on this theme called Hangouts On Air. Those are basically Hangouts anyone can tune in to via YouTube. Up to 9 folks at a time can hang out, all others get to watch. We (board) thought it would be cool to use this as a new discussion platform for the OpenStreetMap US Community. So we are going to try this out and host our first OpenStreetMap US Virtual Mappy Hour, next Monday, November 12, at 5:30PM Pacific, 8:30PM Eastern.

The link will be posted on the Mappy Hour Google+ Event page on the OpenStreetMap US Chapter Google+ page for details and come hang out (and likely iron out some kinks as we figure this out) next Monday.

As for discussion topics, I would love to talk about how to guide the temporary invasion of armchair
mappers in the upcoming Operation Cowboy. If there’s interest, I could also talk about what the board has been up to. But it’s not a formal meeting, so let’s just see where (and how long) it goes.

For those without google accounts: The YouTube channel is supposedly open to the public. If you want to say something, we can dial you in. Let me know in advance if you want me to do that.
Finally, please be aware that a recording of the hangout will remain available on YouTube for anyone to watch at any time.

See you at the Virtual Mappy Hour!

Un-Zorro-Tron – The 90 Second Video

Folks tell me that the Un-Zorro-Tron is less intuitive than its predecessor the Remap-A-Tron. So here is a 90 second video that shows you what a Zorro way is and what to do about them.

UN-ZORRO-TRON 90 sec instructions from rhodes on Vimeo.

If you don’t have 90 seconds, here’s a 60 second video:

If you don’t have 60 seconds, a picture may tell you more than 1,000 words:

Google Maps and OpenStreetMap Data Views – Find The 10 Differences

Google Maps had The Atlantic over for a chat about how they work up their ‘deep map’ from various sources. It’s interesting to read about how Google invests incredible amounts of money and manpower to try and do the best job possible of capturing ground truth without people on the ground.

The article contains some ‘data views’ of Google Maps data in various stages of being worked up. I don’t know if it’s actual screenshots of an editing environment, but regardless, it’s an interesting peek behind the scenes that I had not had before.

This is from the article:

The Google Maps editing environment. Source: The Atlantic

This is about the same area loaded into the OpenStreetMap desktop editor JOSM:

The same area in the OpenStreetMap editor JOSM

Now you can look long and hard to try and make out ten or maybe a hundred differences in the data, but there’s one difference between these two views that reaches much deeper. The data behind Google Maps you will never get to see, let alone touch. The data in OpenStreetMap on the other hand is there for anyone to download, use, make great products out of and, most importantly, edit and improve. That difference marks a cardinal characteristic of the Google Maps platform that the article failed to raise. Consider that itch scratched.

Submit your session proposal for SOTM USA

It’s been a while folks. I have been working on some exciting OpenStreetMap related things that I am eager to report on, but preparing to teach my first academic course has taken up a lot of my time lately. By the way, the course is an advanced GIS course, and it’s fully online, so if you want to brush up your GIS skills, you should enroll! Drop me a line if you’re interested. But now on to relevant matters!

The deadline for session proposals for the State of the Map USA conference is on Friday, August 31, so submit your session idea soon. The conference will be made up for talks by community members on everything from tools and techniques to working with and contributing to OSM data to showcases of it in use by companies, governments, nonprofits, and everybody to bigger picture discussions of where OSM should be moving in the future.

The State of the Map USA conference will bring together people working with, adding to, and advocating for OpenStreetMap. Our community is filled with people doing interesting, cutting edge, and important work. This is your chance to share it with us all.

You can submit your session proposal here – we just need 200 words or less about what you want to talk about. If you have questions, email me or hit us up on Twitter at @sotmus.

Crumpled City Maps, Made With OpenStreetMap (And Other Data?)

We got this freaky crumpled map as a gift to bring on our upcoming trip to Rome. It’s made with OpenStreetMap data.

Crumpled City Map - Rome

Crumpled City Map - Rome

Crumpled City Map - Rome

Crumpled City Map - Rome

Crumpled City Map - Rome

Crumpled City Map - Rome

I wonder if they used any additional data and if so, did the publishers follow the directives of the CC-BY-SA license of the OpenStreetMap data? I see things appear on my crumpled map that are not currently in OpenStreetMap. An example is Parco Savello:

Crumpled Map - detailOpenStreetMap does not have this park at all:

Map data (c) OpenStreetMap and contributors.

If they did use other sources together with OpenStreetMap to make these maps, the resulting database derived work should also be licensed under CC-BY-SA. Does anyone know if that is the case?

Looking ahead – Important Topics For SOTM US 2012

I posted this message on behalf of the State Of The Map US 2012 Committee and the OpenStreetMap US Chapter Board out to several lists this morning:

Call for bids to host the second State Of The Map US Conference

The OpenStreetMap US Chapter is currently soliciting bids for 
hosting and organizing the State Of The Map US 2012 conference
(SOTMUS12), to be held in the second half of the year. We invite
you to put in a bid for SOTMUS12, considering the criteria
outlined on the OpenStreetMap wiki - see the links below.
The US Chapter board will work closely with the selected bid team
to make SOTMUS12 a success.
Please enter your bids as a sub-page on

The bid criteria are here:

The deadline for entering your bid is 31 January 2012. The winning
bid will be announced by the SOTMUS12 committee on 10 February 2012.

If you have any questions, do not hesitate to contact the bid
committee through Martijn van Exel,

We look forward to receiving your bids!

The SOTMUS12 bid committee and the OSM US Chapter

That means we are going to have another SOTM US this year! I could not be more excited and am looking forward to seeing the bids for hosting this wonderful event come in.

The first and last proper SOTM US was held in Atlanta in 2010. The ‘main’ SOTM conference was held in Denver last September, so there was no real need to host a separate SOTM US – but now we’re in 2012, so a new regional State Of The Map is called for. Off the top of my head I can identify three key challenges more or less specific to the US that I would personally love to see addressed at this conference:

  • Community Expansion – Although the US community has some really committed members who spend countless hours improving the US map, we need to think about expanding the community. First and foremost, we need many more local communities and thus more local community leaders. There are still major cities without a real OSM community (people getting together, organizing local events) and it is my belief that without that, you will never get the best map there can be. Second, we need to find ways to leverage more casual mapping. This is a global challenge for OpenStreetMap, but particularly in the US, where we lean so heavily on imported data, there is lots of room for microtasking and single-purpose editing tools to allow people who don’t want to invest a huge amount of time in learning new skills to contribute by fixing small things.
  • Corporate Interest – Early corporate adopters of OpenStreetMap data in the US – CloudMade, MapQuest, Microsoft – have all contributed back to the community in awesome ways – with community support, sponsoring, free tools, data mirrors, aerial imagery and lots more. 2012 may very well see more corporate interest. How is OpenStreetMap going to channel that interest and ensure that we will continue to keep that spirit of mutual benefit alive? What can we, as the OpenStreetMap community, do to accommodate large scale data consumers? Is it our job to do that? SOTM US will be a great place to address those questions.
  • Government Collaborations – With pretty much all US government produced data being in the public domain, there is a certain self-evidence to the mutual relevance between OpenStreetMap and US governmental institutions tasked with maintaining geospatial data. The USGS has extensive experience with crowdsourcing techniques and have been working with OpenStreetMap for some time now. With the government budget situation being as it is (do I hear someone mention Iowa?), I expect an increasing number of government agencies will start looking into crowdsourcing as a way to keep up with changes in the real world. Collaborating with OpenStreetMap would be a good way for them to jumpstart crowdsourcing initiatives, but there are many open questions around authoritativeness and licensing. Again, State Of The Map would be an excellent platform to discuss them.

I am just scratching the surface with these three topics. I am sure that we will see a varied an interesting program that will attract community members, techies, delegates from (mapping) companies, academia and government alike, and I hope that you will be among them at SOTM US 2012 – wherever it will turn out to be!

Happy bidding!

Aerial Imagery for OpenStreetMap

Anyone can contribute to OpenStreetMap, and there’s several complementary techniques for mapping. One of them is to use aerial or satellite imagery that has been cleared for use as reference material for OpenStreetMap. Yahoo! was the first company to grant such a license on their worldwide imagery to OpenStreetMap. More recently, OpenStreetMappers have been able to trace over Bing aerial and satellite imagery, which meant an increase in resolution and coverage for most regions in the world.

Editing OpenStreetMap with the help of Bing imagery

There have also been special cases where companies have provided imagery resources for smaller geographical areas, as was the case after the Haiti earthquake. Many national, regional and local governments have aerial imagery available as well, and some have provided their imagery to OpenStreetMap for mapping purposes (here‘s an overview).

Why are local OpenStreetMap groups and individuals engaging with their governments to gain access to aerial imagery when OpenStreetMap already has Bing as a great, worldwide resource? There are many. Bing does not cover the whole world in high resolution imagery, which is needed to map roads, buildings, sports facilities and most other features you see on the map. Where high resolution imagery is not available from Bing, local resources may be able to fill the gap.

Another reason for wanting to use local aerial imagery is currency. Bing imagery can be years old – the age of the imagery varies greatly. Without local knowledge it can be hard to establish what the age of the Bing imagery for your region is, although this tool can help. If the Bing imagery is more than a few years old for the region you want to map, you will not be able to derive the latest changes – new roads, a new residential area, a torn down baseball stadium – from that imagery. Mappers who are unaware of the age of the imagery may put in features that are no longer there, or destroy more current information thinking they are actually ‘improving’ the map!

So even though Bing is a great resource for OpenStreetMap, access to local aerial imagery may help improve OpenStreetMap a lot! So if you’re an OpenStreetMap contributor, check with your local government’s GIS department and see what they have. They may be willing to grant OpenStreetMap access to it. If you represent a local, regional or national government and have imagery available, contact a local OpenStreetMap group (or me if you can’t find one) and see how you can help make the free and open world map even better!


I got in touch with the GIS department of the state of Utah right after I moved here, and it turns out they have some great resources. They have 1m imagery from 2011 covering the entire state and 25cm imagery from 2009 covering the major urban areas. You can see the importance of current imagery in this side-by-side comparison of Bing imagery (top) and the state imagery (bottom):

How to add an imagery layer to JOSM

The screenshots are taken right from the advanced OpenStreetMap editor JOSM. It’s really quite straightforward to add a new background image resource to JOSM, provided it’s available as either a WMS service or preferably a tiled map service following the TMS protocol. To add an image resource, go to Edit > Preferences… (F12) and click on the imagery tab (the green one that says WMS TMS). The top part represents all the imagery layers that are built into JOSM by default. The bottom part represents the active layers, and you can add your own there by clicking the grey + next to the list. A smaller window pops up; this is where you add the imagery layer details: its name (you can make that up) and the base URL of the WMS or TMS service.

For WMS, that’s the URL of the service without any of the WMS parameters. Clicking ‘Get Layers’ will retrieve the available layers from the service and present them. All you need to do is select the layer you want to add and press OK. The layer should now appear in the Imagery menu of JOSM. In the case of the Utah imagery, the URL is

For TMS, the process is a little different: you need to figure out which parts of the TMS URL represent the zoom level and the x and y location of the image tile in the URL, and insert them as {zoom}, {x} and {y}. Look at the default layers if you get confused. The provider of the service will also be able to help you figure it out!

Don’t forget to always get permission from the service provider first! The fact that the service is publicly available does not mean that it’s OK to use it for mapping in OpenStreetMap! Discuss with the provider of the imagery, and if in doubt, get in touch with the community through the legal-talk mailing list or IRC. And don’t forget to document the imagery on the wiki: edit the relevant page for your region, town or country, and add the resource to the Imagery Overview page.

Voting for the 2012 OpenStreetMap US Chapter Board is open

UPDATE: I got elected! Looking forward to this challenge a lot. I wish there was a stronger mandate from the community – there really weren’t very many votes. This is one of the things we will focus on: getting more people to join the OpenStreetMap US Chapter, and give them good reasons why they should.

The board of the US Chapter has run its term and it’s time for elections! After a nomination period which ended a second before midnight today, the voting period has now begun. This means that any paid up member of the OpenStreetMap US Chapter can cast their vote for up to five of the nominees. The details are all here, including the list of nominees.

Needless to say, if you care about the OpenStreetMap in the US, be it as a community member or as a (potential) user, it is in your interest to have a US Chapter board in place that serves to support the US OpenStreetMap community and its user base. If you’re not a member of the US Chapter yet, you can sign up now and be eligible to vote immediately – voting is open until this Sunday.

If you want to learn more about the US Chapter, head over to the web site. The OpenStreetMap Wiki has some more information about the proposed relationship between the local chapters and the OpenStreetMap Foundation. The Foundation also runs a Working Group that is looking into formalizing the Local Chapter idea.

Surprisingly – to me at least – is that only one of the current board members is running again. With so little experience carried over, it’s going to be a big challenge for the new board to settle into a good routine, picking up best practices from the current and past boards.

Also, I would have liked to see more candidates to choose between.

As I am running for a seat on the board as well, I will not discuss the individual nominees. Luckily, most of them have responded to my call to put up a manifesto, so you can make an informed voting decision if you – like me – do not know all the candidates personally.

What are you waiting for? Sign up if you haven’t already, and vote!