There's this BBC article about #w3w, a proprietary service to "help" determine location, and the police is said to be urging people to use it. Story mentioned how somebody got lost and was instructed by a call-handler to download said app.
Any mapping app on your phone (e.g. Google Maps) can determine your location (if you enabled it).
For the amount of time it took to get the app to work the location could've been given several times over -- just to make sure they got the coordinates right.
@GOwin and I've seen ads saying the same.
If they want something shorter than coordinates, you can get an OLC from Google Maps or OsmAnd without any internet connection. And the (open source) algorithm for that is such that it could be printed on first responders maps if they wanted.
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