Intro To OpenStreetMap

What is it, and how do you use it?

The Concept

What it is

OpenStreetMap is a free, editable map of the whole world made by people like you. It was started in 2004 in the UK, out of frustration with the lack of availability of good map data that was free to use.

• Free
• Editable
• Global
• Twenty years old! 🥳

“Wikipedia of Maps”

Like Wikipedia, OSM:

• Can be edited in almost any way you see fit
• Has a core user base deeply invested in the project
• Experiences occasional vandalism…
• …And swiftly deals with it
• Has endless hair-splitting and meta-discussions

The Organizations

OpenStreetMap Foundation

• Supports OSM, but does not control it
• Non-profit established in 2006
• Does the legal stuff
• Manages the back end

OSM US

• OSMF chapter in 2020
• Emphasis on education, development
• Supports several apps and larger projects
• Building bridges with US government groups

The Users

Data Consumers

Folks who use OSM data in their projects, like:

• Esri Basemaps
• Red Cross
• Amazon Logistics
• Pokémon GO
• Various federal agencies
• Kendall County

Way, way more than we can list. Check it out!

Being a data consumer can seem complex, but you can easily use OSM basemaps or something like the QuickOSM QGIS Plugin to throw some features into your map. Boom! You’re a data consumer!

Contributors

• Folks who edit the map!
• There are over one million contributors so far
• By the end of this workshop, maybe you?

Other Folks

• OSMF and Local Chapter Staff
• Developers
• Working group members

The Dataset

Elements

• Nodes: lat/lon
• Ways: a list of nodes
• Relations: a list of anything

Relations are too complicated to really discuss in an intro workshop, sorry!

To make it clear: ways do not have geometry. It only has a list of nodes, and its geometry is constructed from those.

Attributes

• NO COLUMNS
• NO SCHEMA

Open-ended keys/values

In OSM, we call them “tags”.

{
  "amenity": "fast_food",
  "name": "Burger King",
  "addr:housenumber": "123",
  "addr:street": "Main Street"
}

It’s perfectly valid for an object to have no attributes, too. If it’s just acting as a vertex for a highway, for example, you don’t need to tag it.

In general, if the object participates in a larger object (node in a way, way in a relation), tags are optional.

Inherent Topology

Moving a node will change every way that references it!

This can vastly simplify the editing process in certain situations, like contiguous boundaries or road networks.

For those of you who have ever collaborated on something. Say, boundaries in NG911, imagine if there was no such thing as “snapping your points to theirs”. Imagine if they were the same literal nodes, and your boundaries were just always aligned.

Also, for those of you interested in network analysis, consider: the OpenStreetMap road network is already a series of connected nodes and edges. You can go almost directly from OSM data to routable graphs.

Changesets

• A bounding box
• A list of things you changed
• Exactly what you did to each thing (updated a tag, moved a node)
• Any comments you want to make
• Source specified (optional, but you always should!)

Changesets: An Example

Changeset 141807660

Vandal Stories

Before we get to the editing, I do just want to share a few stories of vandalism, because they’re kind of interesting, and they demonstrate the robustness of the data model.

Pokémon GO

There’s actually an academic paper about this. It wasn’t all vandalism.

Charts from the above-linked article

TO be clear, not everything done by Pokémon GO players was vandalism. The game was an onramp to OSM, and they worked to accurately flesh out the map in their areas.

But still, plenty was. In the early days of the game, it was not uncommon to find factories, power plants, forests, and more, all in a middle school playground. Players were trying to get the rare Pokémon to spawn somewhere more convenient!

Now, the OSM API can be queried in really specific ways. When the OSM community saw this happen, it was a simple matter to query the kinds of features players were adding, specifically coming from brand new users, and even spatially searching within a certain distance of schools.

Saucon

Saucon Support, Saucon Technologies

\[ \begin{equation} \begin{array}{r} & \textsf{Driver Monitoring} \\ + & \textsf{OSM Speed Limits} \\ & \hline \textsf{Incentive to Edit} \end{array} \end{equation} \]

This one’s pretty recent. There are a surprising number of companies like this that use OSM as the reference data for things like driver monitoring. Like insurance companies using your driving behavior to adjust your rates based on how safe you drive! Part of that is: are you keeping at or under the speed limit?

If you can just raise the speed limit, suddenly you look like you’re driving a lot safer.

Hard to say exactly why this particular case was happening, but given that they are a player in the driver monitoring space, it seems like something similar could be happening.

Again, it’s easy enough to query edits like this, where users are changing the maxspeed tag on huge swaths of features.

This one is an example of how the Data Working Group occasionally steps in when the situation warrants it.

More Resources

• The Contribute Map Data page of the OSM Wiki
• JOSM for power users
• Mobile App page of the OSM Wiki
• OpenStreetMap Discussion Forums
• OSM US Slack Space

Editing the Map

(This is the hands-on part.)

Create an Account

Sign Up!

Click “Edit”

1. Go to https://openstreetmap.org
2. Find an area you’d like to map
3. Click the “edit” button in the upper left

Take the Tour!

Seriously, don’t skip it.

Go Forth and Map the World!

• Don’t be afraid to ask questions
• Read the “Good Practice” wiki page
• Pay attention to local / regional conventions

Be in Touch!

josh@jcarlson.page

https://jcarlson.page

@jcarlson@mapstodon.space