CrowdMag

NOAA's National Geophysical Data Center

About this app

Introducing CrowdMag's newest feature: Flight Mode, which lets you contribute to scientific research by measuring the magnetic field as you fly around the world. To get started, simply provide your itinerary on the CrowdMag app, and you'll be able to turn your flight into a scientific expedition. Check out this step-by-step tutorial for measuring data while flying: https://www.noaa.gov/education/resource-collections/data/tiny-tutorials/crowdmag-flight-mode.

CrowdMag is an app that lets you measure the local magnetic field using your smartphone. You can view the data as a graph or a map in nanotesla units. CrowdMag measures the Z (downward component), H (horizontal intensity), and F (total intensity) magnetic field components. You can use CrowdMag for measuring magnetic data during outdoor activities, while flying, or to conduct your own experiments. You can also share it with NOAA to help scientists better understand Earth's magnetic field.

If you're going for a walk, run, or other outdoor activities, you can use CrowdMag to measure the magnetic data along your path and save it as a "magtivity." And, if you get a new phone, don't worry! You can export a backup of your CrowdMag data and save it on your computer. This way, if you have to reset your phone or switch to a new one, you can import your backup and continue using CrowdMag without losing your data or progress.

CrowdMag also has a magnetic calculator that provides magvar (declination), the magnetic field's dip angle, total magnetic field, and other magnetic field components based on the latest World Magnetic Model (WMM2020). Some of the other features of CrowdMag include creating your own magtivities, customizing recording frequency and location accuracy, exporting your data via email or Google Drive, and seeing generalized crowdsourced magnetic data from other users.

And, before we forget, CrowdMag also features a compass that distinctly shows both true and magnetic north. As an added feature, the compass also has a 3D display with an optional audio output - check it out!

CrowdMag features:

* Create your own magnetic activity (called a "magtivity")
* Measure data while flying
* Customize recording frequency and location accuracy to your preferences
* View your magnetic data on an interactive Google Map
* Graph your data as a time series line chart
* Check the quality of your data by comparing it with the World Magnetic Model (WMM)
* Export your data as a CSV file
* Clear stored data on your phone when you want to start fresh
* Choose to share your data with NOAA (optional)
* See generalized crowdsourced magnetic data from other users
* Use the live magnetic compass for 2D and 3D rendering
* View information about the current solar magnetic disturbance
* Use the most up-to-date magnetic field model (WMM2020)
* Export your data via email, Google Drive, or other options
* Export a CrowdMag backup to save your contributions' status and data
* Import your CrowdMag backup (works across different phone platforms)


Visit https://www.ncei.noaa.gov/products/crowdmag-magnetic-data to see crowdsourced magnetic data.

Ratings and reviews

Cool app. Two things: this app needs finer control over sampling rate, maybe a faster sampling rate option. Also, making it so it can be used running in the background would be convenient. I use my phone mag to experiment with surveying, I typically operate it at a faster sampling rate so I can catch smaller anomalies without moving at a snails pace. Being able to create anomaly maps is great but a faster sampling rate would help get better detail.

I wish this wasn't buried in the search results among thousands of garbage compass apps, this app (which is literally from NOAA themselves) is a compass, allows you to calculate magnetic declination and true north, calculate changes in the magnetic field using a model, crowd source (log and contribute) to a magnetic field model, and more. It uses old Android UI elements, but still receives updates (most recent one added a 1 Hz log rate option) so I will not complain.

Very useful to get magnetic declination for anywhere on your phone. Unfortunately last update introduced a bug: WMM and EMAG overlays just show to the west from Greenwich meriduan, with eastern hemisphere data overlaid over the western one in a mirrored way. As if the right half of the map were folded over the left one and left there. It was not this way before. Edit: bumped up to 4 stars after a promise of a fix. Edit2: fixed, and 5 stars

What's new

Updated tutorial links