Smartphone Solutions for Wildlife Biology (Bonus: Custom Maps)

Written by Michael Medina

I began working in wildlife biology back when all we used was a map, compass, and actual aerial photos.  Commercial, high-accuracy GPS units, were available but they were bulky and due to selective availability, required you to collect a lot of data and post-process it back at the office.  It could not accurately tell you where you were in the field. In 2000 selective availability was turned off and consumer units became accurate enough for most uses.
 
Fast forward a “few” more years and I found myself looking at the large, bright display on my smartphone wondering if this device would be good enough for general field work (short answer, yes).  For 2 years, whenever I was in the field, I used and tested 3-4 devices side by side, whichever iOS smartphone I had, my personal GPS unit, a work-assigned GNSS unit, often a Garmin fitness device, and sometimes an Android tablet.

Accuracy Comparison: Waypoints collected at the same point from various devices on different dates at different times

​For general field work, a smartphone/tablet is sufficient in almost every use case.  The main drawback is that some devices will filter out small location errors you would normally see on an unfiltered unit.  This can make it difficult to precisely locate a predetermined point (like a geocache).  When you are moving slowly around trying to locate a point, the OS will interpret this as a location error and will not register the movement.  This seems to be less of an issue now that we have aerial photos which give us context.   

A GPS track from a stationary GPS showing location errors over time

Despite this filtering, your phone will meet or exceed most consumer GNSS units as modern smartphones now support GPS, GLONASS, and Galileo.  Another drawback is the risk/cost of damaging your personal device in inclement weather on rugged terrain.

​GaiaGPS
I’ve tried several GNSS apps over the years and settled on GaiaGPS as my application of choice.  It performs the same functions you would expect from any consumer grade GNSS unit with the added features available from a smartphone (a big bright touchscreen, a camera, and easier keyboard use).
 
GaiaGPS is an (paid) iOS and Android GNSS application.  It costs $20 or $40 per year depending on your license but is free to emergency responders.  There are differences between iOS and Android versions but I do not have access to Android devices for testing.
 
Data Collection Types:
Waypoints
Tracks
Areas (polygons)
Routes (straight line or routed)
 
You can attach photos and notes to each of these.
 
The notes will be exported in your KML/GPX and can be added to your attribute table as a single field.  If you are good with scripting, you could manipulate your KML/GPX into something resembling attributes before importing it.
 
GaiaGPS vs. ArcGIS Collector
ArcGIS Collector is frequently used for biological data collection. It’s well thought out and implemented for GIS-centric data collection (for the most part).  I almost always need something Collector doesn’t offer and here is where GaiaGPS fits in.  The chart below highlights some of the more important and useful differences between GaiaGPS and Collector.

Relevant differences between GaiaGPS and ArcGis Collector

Various Screen Shots

GaiaGPS and Custom Web Maps
GaiaGPS offers dozens of map sources for download, hundreds if you count the US Hunting Overlays.  Most of these are high quality, some are authoritative, others are open source and/or are so complex they need to be verified before use (Public Land).
 
You can import and download any maps served by a web Tile Map Server (TMS).  If you are looking at a global web map and you want it to import it into GaiaGPS, there’s a good chance you can.
 
To add maps to your phone, GaiaGPS offers an online tool or you can create a TileJSON file here.  The TileJSON file can be dropped it into the File Sharing pane in iTunes (iOS version).
 
When adding custom maps, you are looking for map tiles served in this format:
Example URL from OpenStreetMap: http://c.tile.openstreetmap.org/5/15/14.png
How you change for use in GaiaGPS: http://c.tile.openstreetmap.org/{z}/{x}/{y}.png
 
If you happen across a map you want to add, sometimes you need to do a little detective work. You can right click on the map and open a map tile in a new window or view the page source/elements/network activity to see the map tile URLs.  If they are formatted like above, you can add them to GaiaGPS.  I’ve discovered several cool maps that I can add to GaiaGPS this way.
 
If you’re a Mapbox user (and you should be), you may have noticed the URL scheme above matches the Carto Share URL minus your Mapbox access token.  Any data layer you add to Mapbox can be added to GaiaGPS using the Carto URL.  You can add MBTiles, KML, GPX, GeoJSON, Shapefile (zipped), CSV or GeoTIFF to Mapbox and then add them to GaiaGPS.  You can finally take that cool choropleth map on your hike!
 
Mapbox compatibility gives you a lot of flexibility with your data.  You can have a custom map layer with only GeoTIFFs, a layer with only contours, a hillshade-only layer, or a layer with vector points from a shapefile you downloaded from a geospatial library somewhere.
 
The smartphone is a great solution for many applications.  In addition to it being an integrated GNSS solution, it contains a still camera, video camera, and an audio player and recorder.  I’ve had occasion to use each of these functions both before and after the smartphone revolution and it is much easier to carry a single device in your pocket than each device in your pack.
 
Resources
https://gaiagps.com
https://doc.arcgis.com/en/collector/