Our first app Posmo Segments is now available on the AppStore and on Google Play.
It will be followed by the Posmo One app which does automatic transport mode classification and tracking.
The Purpose
The purpose of Posmo Segments is to label movement data, a precondition for any supervised machine learning to classify transport modes. But instead of only doing this in-house, we wanted to crowdsource the labeling for three reasons:
- Transparency & accountability: Make the process transparent. Show what type of data is collected.
- A tool for other researchers: Creating POSMO Segments enables any researcher to record well labeled movement data.
- Localization: Our current intuition is, that it might be very hard to find a generalizable model over all geographic areas. It is therefore important to have well labeled data for specific areas.
App How-To
- Approve or click “Always Allow” for location on iOS, allow location on Android. If you don’t approve location tracking, you will not be able to move the slider to start recording.
- Approve the Privacy Policy and the Terms of Service.
- Sign up with email and password
- Tap the transport mode button — per default you’ll see the walk icon — to get to the overview of all available transport modes. The most common transport modes are on top, the less common ones below. Scroll down to get an overview of what is available.
- Choose the Transport Mode you want to record, e.g. “Bike”
- Now the button icon has changed to “Bike” and you can start recording. Slide from left to right.
- Slide back when you want to stop the recording.
- After a few seconds, you’ll see your segment (picture on the left)
- If you did record more than you wanted, you can adjust your segment by sliding back (picture in the middle).
- Click Save if you want to transmit your segment to posmo.datamap.io
- After saving, your segment looks like the picture on the right
Note:
Per segment, we recommend to record less than 90 minutes of data to avoid problems with transmitting or visualizing the data.
Posmo on the web
Go to posmo.datamap.io and log in with your email and password. Every segment you have saved, will be immediately available for further analysis.
You see a list of all your segments with the latest on top. If you click the checkbox, you can either delete the segment or download the file as csv (see image below).
As we record at 50 Hz, you get 50 rows per second. GPS data — e.g. longitude and latitude — is available around every second, whereas accelerometer, gyroscope and magnetometer data is available 50 times per second.
However do not expect the data coming in at precise intervals.
Finally, if you click on any segment in the list, you’ll get to the map, altitude and speed view.
You can scroll horizontally along the timeline to see where you stopped and for how long, where you were at maximum speed, where you slowed down (e.g. entering town) etc.
