A project I worked on, the Toronto Public Washroom Import recently finished up and I thought it would be interesting to do a quick lessons learned:

Top three things that went well:

• Having help from other people makes things much easier — I am grateful to RockTeam for helping with the changesets and for Jarek_Piórkowski and a couple members of the Civic Tech Toronto community for their input on the import plan.
• Doing a couple “test” imports and recording an instruction video significantly improved the written import plan and instructions. It’s also very helpful to have mapped a couple of the relevant features via survey as well.
• For the script that converted the City data to OSM tags, setting and validating assumptions about the City data using Pandera helped give me a lot of confidence that the output wouldn’t be affected by upstream changes to the City data.

Top three things I would change if I did it again:

• Increased the time assumption for how long it would take to complete all the changesets. I had originally expected it would take two weeks at most, but it took closer to three (even with two people doing changesets).
• For the initial data profiling, I might try using e.g. Tableau public, since it would be a little faster and easier than e.g. using .value_counts(dropna=False) in pandas.
• Have the data transformation script estimate how many washrooms should be conflated vs. net new in each changeset - this would provide a simple comparable metric to ensure that the conflation plugin was configured correctly for each changeset.

Top three resources that were helpful:

• I found OSMCha incredibly helpful both to track changesets for the project and to explore other changes being made to amenity=toilets features by other users within a specific area.
• The Import Plan Outline is very helpful and clearly battle-tested. The only improvements I would suggest to it would be to add a couple “good examples” of the template in use.
• The OSM Queries website helped me get a better understanding of how to write the Overpass queries I needed for this project and was much easier to understand than the query language wiki page.

Top three resources that could be improved or should exist:

• More documentation or guides that help users successfully plan and execute data imports. The Import Guidelines are very helpful, but primarily focuses on compliance with community norms, so it would be helpful if there was more “how-to” or “tips” style documentation. The Import/Software documentation is also narrowly focused on software that interfaces with OpenStreetMap itself, and it is harder to find good guides on software that helps with other parts of the process (e.g. data exploration and transformation, group coordination)
• Some of the JOSM “how-to” documentation would benefit from some examples and additional attention, but it would be really helpful to have a good set of how-to videos, especially for the conflation plugin. I also like the format in this how-to by Koreller with easy to follow GIFs.
• When trying to understand the nuances of certain tagging, I found myself searching through several different places, e.g. wiki discussion pages, old mailing lists, new community forum posts, user diaries, etc. It would be helpful if there was a good unified search tool that would make it easier to find all of the relevant discussions of a topic across all these different official OSM platforms.

My final takeaway - doing this project was a bit daunting, but I feel like I’ve gained a much deeper knowledge of tagging certain features as a result, and now I have some great past experience I can build on if I find another dataset worth importing.