9 August 2009

Creating a detailed map with Walking Papers

One of the things I learned about at SOTM, is the existence of walking-papers.org. This tool renewed my interest of mapping around my house in order to create an higher quality map. During SOTM, we were often presented with examples where OpenStreetMap was more accurate and more detailed than commercially available data. I think I just contributed to that!

First of all, what is Walking papers. It’s a simple web site where you can print a map of an area. You go walk around and note the missing information. When you come back, you scan the page and upload it back. From Walking papers you can edit the map using your scanned page as the background to the online Potlatch editor.

Since I am not a big fan of Potlatch (and that I gave away my scanner, not having used it for years), I used the paper as a reminder of what’s on the land when editing with Josm.

Before SOTM, I never though about the high value of extra data (other than ways). Now I highly value all the small details, such as mail boxes, restaurants and addresses. The last one is pretty boring to do by the way. It requires a lot of note taking and a lot of nodes to create and edit. But addressing will be the ultimate step to make precise routing possible with OpenStreetMap data.

So here is what I did (with a friend for Saint-Laurent and Prince-Arthur streets) over the week-end. This represents about 4 hour person walking on site and 4 hour person putting all the data back in the computer. I included a screenshot of Google Map’s Tele Atlas data just as an example to show how far they are from having complete data.

Note: The before screenshot dates after the first pass on Prince-Arthur.  I didn’t do the streets north of Prince-Arthur street yet, that’s why OpenStreetMap is missing a park. I’ll add it when I see it with my eyes (we should never copy from other map sources).

I am really happy with how the Square Saint-Louis renders.  Unfortunately, the square’s page is only available in French on Wikipedia.  The square is bordered with Victorian style houses from the 1880s.  The square itself dates from the same years and has never lost its charm.  In its first years, it was where the upper French Canadian class settled.  Avenue Laval is bordered by georgious victorian houses.  I hope I could buy one some day, those houses are just very nice and we should protect them.

Comments (4)

  1. 10 August 2009
    Thomas van der Burgt said...

    Very impressive! Did you add these streets without GPS-data?

  2. 10 August 2009
    Pierre-Luc Beaudoin said...

    I used the Yahoo satellite imagery to add the service lanes (Ruelles in fr_CA). There is an explicit contract between OSM and Yahoo regarding their satellite image so we can map from it. I traced all the paths in the park from paper but since it forms shapes it was easy.

  3. 10 August 2009
    Adam Williamson said...

    What’s OSM’s plan to avoid bitrot? Restaurants open and close, addresses are adjusted (new buildings get built all the time, though in countries which use block systems this isn’t as much of a problem), even post boxes can get moved around…

  4. 11 August 2009
    Pierre-Luc Beaudoin said...

    There are no such plans but to have people use the same technique and validated the data routinely. There are also systems that exist to simply report an error or missing element and that’ll warn mappers in that area such as http://openstreetbugs.appspot.com/