Mobile phones and mobile GIS — TerraLab - Environmental and GIS consulting (2024)
With the advent of mobile GIS, more and more organisations are turning to mapping with their mobile phones. I mean, why not? Staff are often required to carry them for communications purposes, so why not leverage the GNSS device located inside for your mapping?
One comment we often hear, is that the accuracies are poor. But are they? We’ve compiled some data on the horizontal accuracies of some popular, late-model (as of the time of writing) mobile phones below so that you can compare for yourself.
The fine print
We didn’t do these tests ourselves. Rather, we referenced data published by the USDA Forest Service who tested these devices under a range of tree canopy conditions. The data presented below is:
From 60 positions, averaged.
Without an external antenna.
With a WAAS real time correction (unless specified otherwise).
The tests are reported as being conducted using Geospatial Positioning Accuracy Standards: Part 3: National Standard for Spatial Data Accuracy (NSSDA Standards).
Additional Notes:
The NSSDA Horizontal Accuracy calculates a 95% confidence level (i. e. 95 out of 100 times the GPS accuracy will be equal to or better than NSSDA calculated distance from the true location).
Some results are an average of more than one test run.
Data is collected after allowing sufficient time for the GPS device to acquire a current almanac and ephemeris data.
We took the reported horizontal accuracy under the conditions presented above and applied a buffer equal to the horizontal accuracy, to represent the accuracy as a circle around the central position. This is intended to be a visual aid, as many people are familiar with the accuracy bubble that appears around a user’s location on mobile mapping applications.
The Apple iPhone 13 shows a very even degradation in reported accuracy, based on the level of canopy cover. In the open sky it reports an accuracy of 3.95 m. Under a heavy canopy, this degrades to 8.6 m.
In an open sky setting, the Google Pixel 6 reports the best horizontal accuracy of the devices presented, with an accuracy of 2.7 m. The heavy/closed canopy accuracy of 4.19 m is also better than all other devices listed here for light/medium canopy conditions.
The Samsung Galaxy S21 is the closest match to the Google Pixel 6, with an open sky horizonal accuracy of 2.75 m. Similarly to the Motorola, the device doesn’t appear to be heavily impacted by the amount of canopy cover, with light and heavy canopy cover accuracies being very similar.
And finally, the Xiaomi Mi 9 with an open sky horizontal accuracy of 4.1 m, ballooning out to 12.03 m under heavy canopy cover conditions. Of the devices presented, this is the only device that did not utilise a Satellite Based Augmentation System (SBAS) in its position, which seems to have had a significant impact on its location accuracy, particular under heavy canopy.
Mobile GIS is considered as an integrated software/hardware framework for accessing spatial data and services through mobile devices via wireline or wireless communications (e.g., WiFi, broadband and Bluetooth; Tsou, 2004). Simply put, it refers to GIS for use on mobile devices.
Based on open sky conditions, the Google Pixel 6 has the best position accuracy at 2.7 m, followed very closely by the Samsung Galaxy S21 at 2.77 m. The Motorola One 5G comes next at 3.22 m, and the Apple iPhone 13 trailing that at 3.95 m.
A Geographic Information System (GIS) is a computer system that analyzes and displays geographically referenced information. It uses data that is attached to a unique location.
Some of the disadvantages include the high cost of purchasing and maintaining a GIS system, the need for specialized training to use a GIS system, and the potential for misuse of data.
In addition to pure GNSS positioning, current smartphones use inertial sensors (such as gyroscopes, accelerometers, and barometers) and network-based positioning (which rely on cellphone networks and Wi-Fi). These different technologies help compensate for the lack of GNSS satellite signals.
Cell phone GPS technology relies on the Global Positioning System, a network of satellites that transmit signals to GPS receivers. By measuring the distance between the receiver and multiple satellites, the cell phone can calculate its precise position using the principles of triangulation and trilateration.
Global Positioning Systems or GPS are used to find the exact location of things.Geographic Information Systems or GIS are used to record information on to maps.
Google maps only show you what the naked eye can see on the surface; GIS maps show you all the things that are above, underneath and invisible (but very real), plus historical info so you can predict the future.
These maps, graphs, statistics and cartograms display geographical features like location, natural resources, streets and buildings as well as demographics. In its most recognizable form, a GIS visualization is what you see when you route a trip on Google Maps.
Introduction: My name is Tish Haag, I am a excited, delightful, curious, beautiful, agreeable, enchanting, fancy person who loves writing and wants to share my knowledge and understanding with you.
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