A heatmap released by Strava visualises users' running routes and activity across the world
A fitness tracking app has come under scrutiny after indications that a map it released revealed details of movements at military bases.
The issue was raised as analysts examined a so-called heatmap released by Strava - a 'social networking' website & app that uses GPS technology to track and log activities such as running and cycling.
Data can be uploaded to Strava's platform through commonly used devices such as Fitbits.
The heatmap was released in November 2017 - using data gathered up until September of last year - with the company saying it took 1 billion activities to create a "direct visualisation of Strava’s global network of athletes" around the world.
Although the map clearly shows higher levels of activity around cities and population centres, it is detailed enough to highlight more isolated areas where unusually high levels of activity have been tracked.
While the global map was initially released several months ago, concerns about its apparent mapping of military bases were raised over the weekend by Nathan Ruser - an analyst with the Institute for United Conflict Analysts.
Strava released their global heatmap. 13 trillion GPS points from their users (turning off data sharing is an option). https://t.co/hA6jcxfBQI … It looks very pretty, but not amazing for Op-Sec. US Bases are clearly identifiable and mappable pic.twitter.com/rBgGnOzasq— Nathan Ruser (@Nrg8000) January 27, 2018
He pointed to apparent bases in Afghanistan and Syria where activity had been logged, where the data seems to clearly identify commonly used exercise routes.
Mr Ruser observed: "If soldiers use the app like normal people do, by turning it on tracking when they go to do exercise, it could be especially dangerous.
"[One] particular track looks like it logs a regular jogging route. I shouldn't be able to establish any Pattern of life info from this far away."
The revelations sparked immediate concern among security forces & experts, with The Washington Post reporting that the US-led coalition against the Islamic State has already moved to revise its guidelines 'on the use of all wireless and technological devices on military facilities'.
In a statement quoted by CNN, meanwhile, Strava said: "Our global heatmap represents an aggregated and anonymised view of over a billion activities uploaded to our platform. It excludes activities that have been marked as private and user-defined privacy zones.
"We take the safety of our community seriously and are committed to working with military and government officials to address sensitive areas that might appear."