Re: FAA To Finally Ditch Floppy Disks & Win-95

On Sun, 22 Jun 2025 15:49:57 GMT, Charlie Gibbs wrote:

On 2025-06-22, rbowman <bowman@montana.com> wrote:
 

On Sat, 21 Jun 2025 21:24:07 -0400, c186282 wrote:
>

   Still wonder about the Babylonian base-60 thing ...

>
Yeah, every time I have to convert degrees/minutes/seconds into
something I can work with. The jury is still out if that can be blamed
on them or not. The French tried to metrify that and more or less
failed.

 
Fortunately, my GPS (thank you, Garmin!) lets me select the notation
when entering latitude and longitude.  Some sources write it as
degrees/minutes/seconds, some use degrees/minutes with decimals, some
use decimal degrees.

Geocaching uses decimal minutes so I've gotten used to that. However
that's strictly a display option. If you look at a gpx file the way points
are decimal degrees like

  <wpt lat="46.857333" lon="-113.989017">

Track points are the same, luckily. I dump the gpx track of my walks from
the Zepp app to play with them. Finding the distance traveled is easy by
iterating through the points and summing the deltas. Not so easy if they
were in decimal seconds. 

We allowed users to configure the display values to decimal degrees,
minutes, or seconds as well as UTM and USNG but the values were stored as
double in decimal degrees. Your average dispatcher has no idea where any
of them are.

One of the VPs was enthusiastic about WhatThreeWords so I did a demo
build.

https://what3words.com/elder.wallet.corner

I was surprised when I visited a client site and found the dispatchers
like it. You need an app on your phone so you can tell them you're at
aardvark petunia frisbee. 

I was skeptical on several counts. w3w divides the world into 9m grids and
assigns each square to a string. They hold the keys, literally, since
there is no logical way to convert the data except by using their
database.  Adjacent squares have completely different words and if you're
dyslexic you're screwed;  'aardvark frisbee petunia' may be a thousand
miles away. I suppose it's no worse than USNG that is supposed to make
giving locations easier.

https://www.fgdc.gov/usng/how-to-read-usng

If you want to have real fun with your Garmin set the datum to NAD27. When
he first started a geocacher was using that instead of WGS 84. The
coordinates were about 100 yards away, which is fun when you're looking
for a hidden ammo can on the side of a mountain.