Thread by @MappingSupport

1/12 Any reporters here? I have a story for you related to fires and all other emergencies. When a cell phone is used to call 911 the call center (PSAP) always gets "Phase 1" coordinates which is the location of the cell tower. Caller might be several miles away. #KincadeFire

2/12 The PSAP *might* get "Phase 2" coordinates and an uncertainty value (i.e. accuracy). Guess what? Those coordinates are intentionally dumbed-down compared to the coordinates the caller's phone can produce. <== No one knows this! #TickFire

3/12 Do this Google search: congress 911 glonass
The USA has a satellite constellation (GPS) and Russia has a satellite constellation (GLONASS). Starting with the iPhone 4s most cell phones use data from both sets of satellites to determine coordinates.

4/12 But "Phase 2" coordinates use *only* data from USA satellites. This means that in heavy forest or other places with a poor view of the sky the data from USA-only satellites might be insufficient to produce *any* coordinates.

5/12 When that happens, the PSAP never gets "Phase 2" coordinates. <== Public does not know. If caller cannot give an address or description of their location how can responders find them? All of this is the reason I wrote the webpage FindMeSAR.com as a public service.

6/12 The PSAP can ask the caller to browse to that web page, give permission, wait a few seconds for the accuracy to get to 50 ft or less. If necessary, tap "Next format" button until yellow screen appears.

7/12 If you do this Google search: 911 location problems
you can read lots of stories that all trace back to "Phase 2" coordinates that were either never produced or had worthless accuracy. But none of those stories explain the reason (see above).

8/12 Here is a recent Reddit thread I started in a subreddit where 911 dispatchers hang out.
reddit.com/r/911dispatche…

9/12 I am 100% baffled why a feature like this isn't built into iOS and Android. Yeah, iOS has a compass app that can display coordinates. The font is small and the format (degrees minutes seconds) is not the one used by PSAPs (decimal degree). And there is no accuracy value.

10/12 IMHO FindMeSAR should be taught to everyone in middle school. The kids can teach their parents. There is an icon that can be saved on the homescreen. The first time you must be online. Afterwards it works offline.

11/12 Assume you have previously opened FindMeSAR and saved its icon on your screen. You need to call for help but your cell connection is so weak you can only text. Open FindMeSAR, yellow screen, wait for good accuracy, tap ‘stop'.

12/12 Copy your coordinates and accuracy and include that data in your text.