Making OpenStreetMap the Authoritative Source

A Model for Government Engagement with OSM

Josh Carlson

• GIS Developer for Kendall County, Illinois
• OSM Contributor since 2017

OSM, in a nutshell

• Free
• Global
• Editable
• Open-ended data structure

Basically, anyone can create an account and start making changes to the map as they deem appropriate.

This fact makes people nervous about OSM’s reliability. If the data can’t be secured from unwanted edits, can it be considered authoritative?

What’s “Authoritative”, Anyway?

It’s all about the source

• What matters:
  • Official
  • Reliable
• What doesn’t matter:
  • Means of access

We want the data to come from the people who are “in charge” of it. Or if we get it from another place, we want it mostly unchanged.

We also want it to be reliable, meaning it’s reasonably up to date, and seems accurate enough that we don’t need to validate it.

If you are on ArcGIS Online, consider the Living Atlas. It’s full of authoritative data, but most of what you’re seeing is just a copy hosted on one of Esri’s servers. It’s no less authoritative for that fact.

OSM - 2007

Highways and waterways in 2007

Here I want to point out: OSM is full of authoritative data! We talk about it as a crowdsourcing effort, which it is, but there are also a lot of imports.

Roads and boundaries, for instance. These were added from US Census shapefiles back in 2007/2008. Prior to this, most of the US was basically empty.

OSM - 2009

Highways and waterways in 2009

But look at it post-import. Quite a difference!

This means that for a window of time after the import, most of the features in OSM in the US were authoritative federal data.

The fact that these features sit side by side with crowdsourced bench locations doesn’t mean they aren’t authoritative, but it does make it a little harder to tell.

Kendall County

Okay, so what’s our approach to all this as a County?

I was pretty jazzed when I started working at the County. I was on the inside at an authoritative source! Maybe I could facilitate some imports and improve OSM.

I got approval to do so! But it didn’t take long for me to see that for many of the datasets in our “open data catalog”, a lot of it was already in OSM, and it was better.

So it became a two-way process. We could improve OSM, and it could improve our data.

The overall goal was to get everything into the middle of the venn diagram. Everything we had should be in OSM, and everything OSM has should be in our data.

But once you get there… you’re just maintaining two datasets now. You’re doing double work. We don’t want to do double work, so we asked ourselves: what were we doing with our version of the data? Could we accomplish it by using OSM data directly? Was there anything about our tasks that required a siloed / secured dataset?

Make the switch!

For most layers, the answer was clear: using and managing the data directly in OSM didn’t really have a downside, but we would be making our data much more accessible to the broader community. So we decided we would make the switch, and stop maintaining our own copies of a lot of these layers.

Due Diligence

That’s easy to say, but not a decision to be made lightly. We had to make sure we had tools for keeping an eye on the data.

“Data Gardeners”

• Visualize all recent edits
• Color code by user status
  • Internal
  • Known, good
  • Known, iffy
  • Vandal
  • Unknown

I read the term “data gardener” in an article assessing OSM quality, and I love it. We decided we would be “gardeners” for the data in and around Kendall County.

We’re not gatekeepers, anyone’s welcome to edit. But we make sure that edits happening in our area get checked out. We have a QGIS project where we can see recent edits by user type (a table we manage internally). We review these edits at least once a week and address any issues promptly.

For specific feature types like address points, we have more focused review tools to maintain a high standard of data.

But is it authoritative?

By engaging directly with OpenStreetMap:

• OSM is the official source, not a mirror of one
• All edits are reviewed by staff
• Quality has improved across the board

Honestly, I feel pretty comfortable claiming authoritative status for the OSM data in Kendall.

The fact is, there is no other official source of some of this data! And because of how accessible OSM is, the data as it stands today has gotten more detailed and accurate than it ever was before!

Questions?

Be in Touch!

josh@jcarlson.page

https://jcarlson.page

@jcarlson@mapstodon.space