Gaia Topo, as well as several other sources in the app, are based on OpenStreetMap data, an Open-source and public mapping project. You can contribute to this source to make the map accurate and more complete.
Getting started with OpenStreetMap.org
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. Click on the best result.
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
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.
It is helpful to follow the built-in walkthrough on openstreetmap.org.
Editing From the Field
We’re focusing here on using aerial imagery to help improve the map. Another 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 on 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 about restrooms, footpaths, playgrounds, and other features.
This example will use a ballpark, add a missing baseball diamond, and park road to 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, the minor road is added 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, the new road is connected where it begins at Karakung Drive and traced it to its dead end at a parking lot. If you make a mistake, use the undo arrow at the top of the screen.
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.). Path should be used for a generic or multi-use path open to non-motorized traffic. Set highway to track if it is a forest track that allows for motorized traffic.
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. If motorized traffic is permitted you can use the motor_vehicle tag and set it to yes.
- 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 an 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.
Afterward, 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
In this example, the baseball diamond outline is added. You may want to add a body of water, a 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.
- In this example, use the keyword “baseball” in the search box at the top left, then set the feature type for the ballpark to Baseball Diamond.
- Next, enter Reilly Field as its name.
- Leave all unknown values as Unknown, such as "Lit" in this example
- If known, add an address or other information: The address and the website for Haverford Township Little League were added here.
- Don’t forget to Save your edits, and then summarize them in the left pane.
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, for research, and for work.
If you decide to contribute any updates to OpenStreetMap, you'll see the changes in Gaia GPS in the next planet rebuild.
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, and 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.