CrowdMag is a citizen science project that uses your mobile phone. Created by the National Centers for Environmental Information, the CrowdMag app uses your phone's internal magnetometer to record magnetic field values. This tutorial helps you to properly use the CrowdMag app during flight journeys.

 Learn more about Earth's magnetic field from the NOAA Geomagnetism group.

Instructions

Step 1: Download

Download the CrowdMag mobile application from Google Play or the Apple App Store. 

Step 2: Initial Recording Setup

After boarding your flight, and before the takeoff, set your phone to its airplane mode. Then go to CrowdMag "My Data" tab and select your flight after tapping the record button. ** Remove your phone case if it includes a magnetic case or closure. 

Step 3: Enter Flight Details

Enter the flight details (three-letter codes for start and end airports and flight numbers) in the pop-up menu. The app provides an estimate of the flight duration based on the great circle distance and average flight speed. The app doesn’t know about weather conditions, such as the current position of the jet stream, so it is a good idea to check your actual estimated flight time and update it in the app. Tap submit. 

Step 4: Take Off and Record

You will see a map of the expected route and tap “graph” to see the expected magnetic field variations along your route. You have not yet started recording. When the flight is taxiing for takeoff, tap the “Take Off” button to start recording. 

Step 5: Keep Phone in One Location

While flying, keep the phone in the same location, if possible. We have had the best results when keeping it in a shirt pocket or in your stowed carry-on bag away from any metal objects. You can also try placing it in the seatback pocket in front of you (but don’t forget to collect it at the end of the flight!) or on your tray table. Do not charge the phone. Try to minimize the usage if you can. 

Step 6: Stop Recording

After landing, turn off the recording if the app hasn’t done that already. Optionally, share the pop-up summary of measurements. The data will be automatically sent to NOAA to help with their science! 
 

Step 7: Review Flight Data

After recording, go to “Magtivity” and select the flight-data. On the map, tap each dot to see the magnetic data. Blue dots indicate areas with a lower magnetic field value. Red dots indicate a higher magnetic field value. On the graph, the gray line shows the expected magnetic values. Does your magnetic data follow the WMM? This example shows data collected on a flight from Denver (DEN) to Cancun, Mexico (CUN). The overall trend of the data is a good match to the predicted magnetic field based on satellite data models. About mid-way through the flight, there is a big “glitch” in the data - this happened when we got up and moved the phone. 
 

Step 8: Export Data

Tap “Settings,” then “Export my data” to export your data. You can email the data in a CSV format. You might want to email it to yourself or a friend so you can analyze it yourself (for example, read it into Microsoft Excel or Google Sheets).