What is Open street map?
OpenStreetMap creates and provides free geographic data such as street maps to anyone who wants them. The project was started because most maps you think of as free actually have legal or technical restrictions on their use, holding back people from using them in creative, productive, or unexpected ways.
Gathering traces
There are many ways of contributing to OSM. Since I wanted to gather information on road using the iPhone GPS I started looking for a suitable app. There are a few but the best one for this purpose seems to be the OSMTrack app.
To use it simply download the app and create an OSM account. Before you set off just click the start button and start driving around. Once you are finished click stop and then the upload button to send the collected traces to your OSM account.
We can pretend this is me using Open street map during the trip.
Finding the trace
Once safely back near a computer you log in to Open street map and click your username in the top right corner and then "my traces". This gives you a list of all the collected tracks/traces. Click edit on one of them, now the real map editing begins. There are a few different ways to do it but I did the following.
Editing the map
Click "Convert GPS track to ways" and "Edit with save". This ought to convert your collected points into a red way. I have noticed that it sometimes refuses to do so, don't know why.
Next I removed the parts of the way that is already in OSM. To do so click on one of the unwanted points and press delete until you are happy. Pressing enter will stop the editing and escape will remove the way completely. Shift+click on another way will connect the two, used to create intersections for example. Pressing X will split the way in two. Perhaps you want to split a way into two different roads. For more information see the Potlatch/Primer.
Now you ought to have what looks like one or more roads added to the map. Before they will show up you have to mark them with the specific type of road it is. There are a bunch of great examples here. To change the type click on the way and then on the drop down at the bottom of the page that says "(no preset)".
Once you are done don't forget to click the save button at the bottom right of the page.
That's it! You are now a contributing member of society, congrats!
Oh, one more thing. I found OpenMaps to be a great OSM viewing app with offline capabilities for the iPhone.
