Map your favorite places, and join a global movement that makes data free and open to all people. This guide will teach you to edit OpenStreetMap (OSM).
OpenStreetMap: More Than Roads
Whether you’re hiking in the woods or driving in town, you can edit the map near you to make it accurate and more complete. OpenStreetMap uses the local expertise of contributors to crowdsource detailed maps of the world, and anyone can use the data, provided they credit OSM.
Started in 2004, the number of OSM editors has grown from 1,000 on Christmas Day 2005, to more than two million today. The services now gains an average of 8,000 new users each month. OSM reached 20 million edits early last year, and its explosive growth shows no signs of slowing.
Reasons to Edit the Map
People contribute to OSM for all sorts of reasons:
- Remote Forests and Trails – While U.S. government agencies like the U.S. Geological Survey provide topo maps to the public for free, the governments of other countries charge a fee for their maps. People have banded together to make free – and sometimes better – maps through OSM.
- Local Maps – Some contributors want good local maps. For example, the OSM map of Berlin is probably better than any map in the world, because the Germans love OSM.
- Crisis – In crisis, mappers pool their efforts to improve the OpenStreetMap so that first responders and emergency aid workers can navigate the affected areas.
And from personal experience, you feel a bit like a better person when you edit the map.
Getting started with OpenStreetMap.org
In the following example, I’ll show you how I made some edits to my own neighborhood.
The first step is to create an account with OSM at http://www.openstreetmap.org/. There are other tools you can use to edit the map, but this is the most common way.
Explore an Area
Enter an address, zip code, or city to search for the area you want to explore. Or, just click the Show My Location button (the arrow below the zoom controls on the right).
Your search results will appear on the left.
The map will center on your chosen location on the right; the place’s tags (attributes, or descriptive information) are shown on the left.
You may not recognize many of the tags, but don’t worry… editing is simple.
Editing OSM
Now, you’ll need to find something that needs to be added or changed. When I first registered with OSM, I didn’t know where to start, but after poking around for a few moments, I found plenty to do.
The basic steps are:
- Click the Edit button at the top of the screen to enter edit mode. Microsoft Bing aerial imagery will load in the right pane, with existing OSM features superimposed on top.
- Trace over the imagery to add roads, buildings, and other missing features.
I recommend you go ahead and do the built-in walkthrough on openstreetmap.org. Then jump in and improve the map near you.
Editing From the Field
We’re focusing here on using aerial imagery to help improve the map. But another way (and some say the pure way) to improve OSM is to collect data directly from the field.
Here are ways you can collect data to help edit OSM:
- Go find out the name of a feature on the map. While tracing from imagery is helpful, tagging new features adds a whole other dimension to the data.
- The next time you’re out on a trail, record what you can do there (hiking, biking, horseback riding, etc.)
- Mark the exact coordinates of features in the field, using an app like Gaia GPS
- Record hikes and drives of unknown roads and trails with GPS apps
Since aerial imagery can be years old, your tracks and waypoints will provide the most up-to-date information for OpenStreetMap. See the end of this article for a list of resources and tools to help you edit the map.
Editing from Imagery
Look at minor roads in off-the-beaten path areas. Parks are another good place to start, since many of them lack information for restrooms, foot paths, playgrounds, and other features. You’ll get a kick out of this, and spend more time than you think fixing your local haunts.
I started by homing in on a local ball park, and found neither the baseball diamond, nor the park road featured on the map.
Adding New Features
To add a new feature, you’ll use the tools at the top of the right pane.
- The Point tool drops a map marker at a point of interest.
- The Line tool traces roads, rail lines, trails, bike paths, footpaths, and other linear features.
- The Area tool lets you add detailed footprints of buildings, schools, businesses, lakes, swimming pools, and more.
No matter which tool you choose, you’ll want to zoom in far enough to be able to mark features accurately.
Line features, as they appear in OSM.
Adding a Road or Path
In this example, I’ll add the minor road with the Line tool, and the ballpark with the Area tool.
To begin adding a road or path (what OSM calls a “way”):
- Select the Line tool at the top of the right pane. Bear in mind that a line should run down the center of the surface. If you’re adding a road, your line should connect to another road that’s already mapped in OSM.
- Click on the point where the center of the new road connects with an existing road. This will create the first node, or point that helps define ways and shapes.
- Follow the course of the road; where it begins to turn, click to anchor a new node that will allow you to swivel and follow its shape.
- Press the enter key (or double-click on the final node) to complete your line. You’ll have a burgeoning sense of accomplishment, but you won’t be finished quite yet.
For this example, I connected the new road where it begins at Karakung Drive, and traced it to its dead end at a parking lot. Your sketch doesn’t have to be perfect, but if you make a mistake, use the undo arrow at the top of the screen. You’ll be an expert at tracing features in no time.
Next, you’ll be prompted to add a feature type for the new road.
- Set the Feature Type to “Road,” then select a subtype (Residential Road, Motorway, Primary Road, etc.). Click the information icon (i) for a description of each type.
- If you’re not sure what to choose, set the type to Unknown Road. (If you’re adding a path, choose Path as the feature type, then select the appropriate subtype.)
Then, name and tag the road:
- Add the name of the road or path. Since the road that goes through the ballpark is unnamed, I left that field empty.
- By default, roads are assumed to be two-way. If your road is one-way, change the value in the One Way field. Add the speed limit, if known.
- You can indicate which types of traffic are permitted in the Access section. If you’re not sure, leave this section empty.
- You can also note the type of surface in the Surface section. Most roads are tagged as paved, which means the surface is sealed with asphalt, paving stone, metal, or other material. If you know the surface is asphalt, you can specify that here. If you’re not sure, tagging more generally as paved or unpaved is fine.
- If you like, you can include additional fields, such as address, phone, and website with the Add field drop-down menu.
- Finally, be sure to save your edits with the button at the top right.
Afterwards, OSM will prompt you to write a short summary of your changes in the left pane. For example, you could write something like “Added a minor road and speed limit.”
Adding a Park or Building
I added the baseball diamond outline. You may want to add a body of water, grove of trees, your place of work, or a favorite restaurant.
- Select the Area tool at the top right.
- Click on a corner or edge of the feature to place the first node.
- Continue tracing around the feature; you’ll see a polygon taking shape as you go.
- When you’re finished, press enter to complete the shape.
OSM offers tools to help you smooth out your tracings. While they won’t help you if you’re tracing a ballpark, they can make outlining buildings and other features a lot easier.
If your square, rectangular, or circular sketch is an “approximate” one that could use a bit of help, complete the drawing, then click on it. A menu of tools will appear on top of your sketch. Click the square-shaped tool (Square Corners) to fix up square and rectangular shapes, or the circle-shaped tool (Make Circular) for circular ones.
Add tags for the new feature in the left pane.
- I searched for “baseball” in the search box at the top left, then set the feature type for the ballpark to Baseball Diamond.
- I entered Reilly Field as its name.
- Since I didn’t know if the park is lit or not (probably not, and I don’t see light poles on the imagery), I kept the value in that field as “unknown.”
- I also added the address and the website for Haverford Township Little League.
- Don’t forget to Save your edits, and then summarize them in the left pane.
- Also, make sure to Tweet or Facebook your changes, and get your friends mapping too.
Your Edits Reach Millions
It may take a few minutes (or hours in some cases) before your edits appear on OpenStreetMap.org, and start to percolate out to other maps and services that use OSM data. When you edit the map, your changes will start being pulled by all of these apps and maps used for so many things, used for fun and for research and for work.
Hundreds of millions of people use OpenStreetMap each day. OpenStreetMap data powers some of the best websites and apps out there, including our own Gaia GPS. Here are a few others:
The newly added features, as they appear to OSM users.
Become an OSM Expert
There are several resources to help you get started with OSM. Learn more at these sites, and happy mapping!
- Video Tutorials
- Beginner’s Guide – A community-maintained guide for beginners.
- OpenStreetMap Wiki – Need help with tags? Get detailed keys, descriptions, and documentation here.
- OpenStreetMap Help – post a question; get an answer.
- FieldPapers.org – This tool makes collecting data from the field and updating OSM easy. Print off atlas pages in advance, sketch and annotate what you see, then upload the photos of your notes. Open your updated Field Papers file in OSM to start editing, based on your firsthand experience.
- Track-Making Apps – a list of iOS track-recording apps that can be used to update OSM.
- Recording GPS Tracks – OSM’s instructions on how to edit the map by uploading GPS traces.