CrowdMag vs PolyProblems
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CrowdMag
This app allows users to measure and contribute to scientific research on Earth's magnetic field using their smartphone. It offers features for recording magnetic data during various activities, including flights, and provides tools for data visualization and analysis.
- Measure magnetic field data
- Contribute to scientific research
- Record data during flights
- Visualize data on maps and graphs
- Magnetic calculator with WMM2020
- Live magnetic compass
- Export data via email/Google Drive
Read full descriptionHide full description
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://geomag.colorado.edu/crowdmag-flight-mode-tutorial . 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://geomag.colorado.edu/crowdmag to see crowdsourced magnetic data .
PolyProblems
This community tool allows students to report physical and social concerns on campus. Users can post photo reports, engage with a real-time feed of issues, and upvote to prioritize problems. It aims to bridge the gap between noticing an issue and getting it resolved, fostering a better campus environment.
- Easy photo reporting of campus issues
- Real-time community feed of reports
- Upvote system to prioritize problems
- Campus-specific utility and social features
- Centralized platform for issue resolution
Read full descriptionHide full description
See a problem? Report it. Make a change. Poly Problems is the ultimate community tool for the Cal Poly campus. From physical maintenance to social and community concerns, we provide a centralized platform for students to voice issues, help others, and improve our campus environment. Whether it's a facility that needs attention or a community topic that deserves more visibility, Poly Problems bridges the gap between noticing an issue and getting it resolved. FEATURES: • EASY REPORTING: Instantly post photo reports of physical or social concerns across campus. • COMMUNITY FEED: Browse a real-time, social feed of campus reports. Stay informed about what’s happening in your area. • UPVOTE & ENGAGE: Support the issues that matter most. Upvotes help the community prioritize which problems need the most attention. • CAMPUS CONNECTED: Built specifically for the student experience, combining utility with a local, social vibe. Don't just walk past the problem—be part of the solution. Download Poly Problems and help us build a better campus today.
Screenshots
Verdict
The clearest difference is rating: PolyProblems at 5.0 against CrowdMag's 4.3. PolyProblems also leads on update cadence (fortnightly vs every 2 months). CrowdMag's advantage is ratings volume (24 vs 1). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
PolyProblems holds the better App Store score, 5.0 against 4.3. That said, the two scores are not equally well evidenced: CrowdMag has 24 ratings behind it against 1, so its average is the more settled of the two.
CrowdMag ships an update every 2 months, PolyProblems fortnightly. The most recent releases landed on September 22, 2026 and October 1, 2026 respectively.
| Parameter | CrowdMag | PolyProblems |
|---|---|---|
| Price | Free | Free |
| Rating | 4.3 (24 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 52.9% of reviews | — |
| Number of ratings | 24 — better | 1 |
| Update frequency | Every 2 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 18 MB | 36 MB |
| Age rating | 4+ | 4+ |
| Developer | University of Colorado Boulder | Taylor Labs, LLC |
In-app purchases
CrowdMag
No in-app purchases
PolyProblems
No in-app purchases









