@olemanriver None of the local SAR teams I've talked to use United States National Grid. The single most popular emergency response land navigation tool in Vermont is the DeLorme Vermont - New Hampshire road atlas. It has it's own proprietary grid plus lat & long (datum not stated). Google Maps will find a USNG, but will not output the USNG of a chosen point. So I regard USNG as a failure.
@ashton I cannot help what other stuff like google maps and states decide to use. Google maps doesn’t state a datum or accuracy either. I just remember being involved before during and after hurricane katrina. And most of the missed opportunities revolved around everyone doing there own thing. Some were using UTM some nad83 lat longs some had old maps from nad27 some state plane coordinates mgrs pluggers or garmin and numbers are just numbers until someone puts an eye out. I know of specific people that might have been alive today if everyone involved with rescue efforts would have not made assumptions. It is one area that the government agencies actually did a good thing by working together to get everyone on the same system. Yes I understand someone using there phone in emergency situations reporting there position. They will read a lat long maybe degree minutes and seconds maybe decimal degrees hopefully the one rescuing makes the right assumptions of which it is. Tak a lat long and have it in both degrees minutes and seconds and decimal degrees. Plot it out assuming they both are one or the other maybe bad cell connection so you can’t hear well. Where is the chopper going to. This very thing happened during katrina and has happened in other disasters. Now you can see the brilliance in the mgrs utm or now for us in usa usng. One who takes five minutes can know how close or say accurate they are by the numbers 8 digits 10 meters a search team can cover 10 digits 1 meter 6 4 etc climbs to say a city location. I am not in Vermont and i am sure they have a good system. Not knocking it at all. But i blarge disasters people come from all over the usa.
When some federal government agency wanted a unified approach to hazardous materials, they made it possible for every federal, state, and local emergency response agency to order a free paper orange book with hazmat guide for every single emergency vehicle in the country. Now the guide is downloadable to your phone, but it's still free.
So where's my free USNG paper topo map?
I don't know how I would explain datum to the rescue folks. Probably something like: As measurements of the earth improve, our knowledge of actual locations improves. The lat/lon of the Empire State Building from a 1935 atlas won't exactly match the lat/lon from Google Earth or from a GPS, but it's likely to be close. It's not worth worrying about.
Using DeLorme, there's great educational value (and maybe some practical value) here: https://www.maptools.com/product/RS-DL-NHVT
Two or more decades ago, I bought a single such ruler for use on USGS topo maps. Seeing the angle that had to be used to interpolate longitudes illustrates the difference betweenn grid and lat/lon in a pretty telling way.
Whenever I try to explain a datum to someone I just say it's the thing you're measuring from. And then I ask them how tall they are. If they say 5'5" I say OK the floor is the datum and we're measuring to the top of your head. Voila.