geoTools vs CrowdMag
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
geoTools
This app provides tools for geological, geophysical, engineering, and geographic work. It helps estimate geophysical quantities like Bouguer anomaly and magnetic declination, and offers a quick coordinate converter. It's designed for professionals and enthusiasts interested in Earth Sciences.
- Estimate geophysical quantities
- Calculate Bouguer anomaly
- Estimate magnetic declination
- Quick coordinate converter
- Geographic to UTM conversion
- UTM to geographic conversion
- Uses IGRF geomagnetic model
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geoTools is a set of tools to use in geologic, geophysical, engineering and geographic work. It includes the estimation of important geophysical quantities, such as Bouguer anomaly, topography, magnetic declination, and so on, and a quick coordinate converter. The ideal companion for a geologist, a geophysicist, an engineer, a geographer, and to any person interested in the Earth Sciences. The easiest and more effective way to calculate the parameters associated to the Earth's gravity field and magnetic field. Convert coordinates from geographic to Universal Transverse Mercator and vice-versa with one touch, using different reference systems. Since 2018 the app uses the new IGRF geomagnetic model to estimate the magnetic parameters. All the tests we've made show very good results. PLEASE NOTICE: geoTools is free, no ads, no purchases, absolutely free! If you use it, please let a review to help us keep upgrading the app. It is simple, fast, and very important to us!
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
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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 .
Screenshots
Verdict
The clearest difference is review sentiment: geoTools at 100% against CrowdMag's 53%. geoTools also leads on rating (5.0 vs 4.3) and iOS requirement (8.1 vs 15.0). CrowdMag's advantage is update cadence (every 2 months vs every 29 months) and ratings volume (24 vs 3). 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.
geoTools 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 3, so its average is the more settled of the two. Written reviews point the same way: 100% of geoTools's written reviews are positive against 53% of CrowdMag's.
geoTools ships an update every 29 months, CrowdMag every 2 months. The most recent releases landed on September 13, 2026 and September 22, 2026 respectively.
| Parameter | geoTools | CrowdMag |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (3 ratings) — better | 4.3 (24 ratings) |
| Positive reviews | 100.0% of reviews — better | 52.9% of reviews |
| Number of ratings | 3 | 24 — better |
| Update frequency | Every 29 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 8.1 — better | 15.0 |
| Further details — not scored | ||
| Size | 17 MB | 18 MB |
| Age rating | 4+ | 4+ |
| Developer | Andre Molina | University of Colorado Boulder |
Customer experience
geoTools
CrowdMag
In-app purchases
geoTools
No in-app purchases
CrowdMag
No in-app purchases








