GPS satnavs and interactive web maps
- If you use a motor vehicle (private or commercial) to travel to your meeting place, remember that the increasingly common Global Positioning Satellite in-vehicle navigation units ("satnavs") are electronic devices just like mobile phones etc, which contain flash memory which can be read under forensic examination, even when the data is nominally erased. This could betray your movement patterns and give intelligence about, or hard evidence of the time and location of your secret meeting.
- Some units also synchronise with your mobile phone, via BlueTooth, in order to download the latest traffic information or map updates etc, and that could leave a trace of whose mobile phone was present in the vehicle at a particular time and location. - See this New Scientist article Why satnavs are a detective's best friend.
- One of the features of such satnav devices is the convenience of setting up pre-set destinations e.g. "Home", something which can be exploited e.g. there have been warnings from the Police about gangs of thieves, who have burgled an obviously empty property, after discovering its location (and route directions) from a stolen satnav. Such pre-set navigation data could also be used by snoopers to track your movements retroactively, and possibly therby betray your meetings with anonymous sources or friends. Sometimes it may be worthwhile not to store very precise navigation endpoint data in such satnav devices e.g. instead of the precise post code or ordnance survey map coordinates or latitude and longitude for "Home" or for "Secret Meeting Location", you could only store the nearest landmark which puts you on the same page of the map e.g. a local railway or bus station or tourist attraction.
- Further research needs to be done, on particular models of satnav devices (including mobile phones with built in GPS chips), to determine if the device actually keeps a logfile of the searches for particular locations, e.g. the file names names and last displayed time and date data, of the individual graphics files used to display a particular grid square on the interactive map display, or if such data is only held transiently in the memory of the device.
Such graphical file data is defiantly logged by online web sites which offer interactive maps, so you need to take anonymous web browsing precautions (e.g. clearing the browsing history and cached data, using Tor etc.) if you are using such general mapping (e.g. Google Maps, Streetmap.co.uk, Multimap etc) or public or commercial transport time table web sites (e.g. Transport for London, Tube, Rail or Bus timetable systems, RAC Routefinder etc.) to plan a route to a secret meeting.
N.B. trying to erase such data from, for example, an Apple iPhone's Safari web browser, which takes snapshot images of the web pages which have been visited, as part of the clever / fiddly touch screen system, is almost impossible, short of re-flashing the whole device (this is a separate issue from the more general one of the easy recoverability of a a lot of supposedly erased data on flash memory devices).