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Groups > comp.os.linux.misc > #68773 > unrolled thread
| Started by | c186282 <c186282@nnada.net> |
|---|---|
| First post | 2025-06-13 22:38 -0400 |
| Last post | 2025-06-18 08:01 -0700 |
| Articles | 20 on this page of 96 — 10 participants |
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FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-13 22:38 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-14 03:35 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-14 00:29 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-14 16:34 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 The Natural Philosopher <tnp@invalid.invalid> - 2025-06-15 00:38 +0100
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-14 23:28 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-15 14:04 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-15 21:44 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-14 22:41 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-15 14:19 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-15 18:45 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-15 22:02 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-16 03:00 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-16 01:13 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-17 03:42 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-16 17:52 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-17 03:49 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-17 01:29 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-17 18:20 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-17 23:06 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-18 14:15 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-18 19:38 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-18 00:02 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Bobbie Sellers <bliss-sf4ever@dslextreme.com> - 2025-06-17 17:30 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-17 22:38 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-18 03:55 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-18 08:03 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-18 16:15 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-18 19:41 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-19 22:25 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-19 23:12 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Chris Ahlstrom <OFeem1987@teleworm.us> - 2025-06-20 08:36 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-20 20:00 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-21 01:34 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Chris Ahlstrom <OFeem1987@teleworm.us> - 2025-06-21 06:50 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-21 19:30 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Chris Ahlstrom <OFeem1987@teleworm.us> - 2025-06-22 06:43 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-21 23:57 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-22 01:15 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-21 21:24 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-22 06:14 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-22 02:50 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-22 15:49 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-22 18:22 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-23 00:40 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-23 11:27 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 01:34 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-24 07:52 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 22:24 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-25 09:20 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-26 03:36 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Andreas Eder <a_eder_muc@web.de> - 2025-06-29 15:20 +0200
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-30 00:01 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-23 18:43 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 The Natural Philosopher <tnp@invalid.invalid> - 2025-06-22 11:43 +0100
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-22 15:49 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-23 01:01 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-23 18:46 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-24 04:52 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-24 05:06 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-24 01:24 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 06:31 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 The Natural Philosopher <tnp@invalid.invalid> - 2025-06-24 10:19 +0100
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 22:25 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-25 02:02 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-25 01:58 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-25 02:17 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-22 15:49 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-22 19:09 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-22 21:55 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-23 02:25 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-23 01:07 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-23 05:52 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-23 05:35 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-23 16:43 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-23 19:11 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 01:36 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-24 04:52 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-24 06:47 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-24 01:02 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Chris Ahlstrom <OFeem1987@teleworm.us> - 2025-06-22 06:49 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-22 15:49 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-22 02:14 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-07-17 03:57 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-07-17 04:08 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-06-18 22:44 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-15 18:36 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-15 22:40 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 rbowman <bowman@montana.com> - 2025-06-16 04:11 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-16 01:30 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-06-16 18:15 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-16 09:35 -0700
Re: FAA To Finally Ditch Floppy Disks & Win-95 Rich <rich@example.invalid> - 2025-06-17 04:00 +0000
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-17 04:22 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 c186282 <c186282@nnada.net> - 2025-06-17 23:11 -0400
Re: FAA To Finally Ditch Floppy Disks & Win-95 John Ames <commodorejohn@gmail.com> - 2025-06-18 08:01 -0700
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| From | c186282 <c186282@nnada.net> |
|---|---|
| Date | 2025-06-24 01:24 -0400 |
| Message-ID | <9M6dnWQWOZIAq8f1nZ2dnZfqn_udnZ2d@giganews.com> |
| In reply to | #69071 |
On 6/24/25 12:52 AM, Charlie Gibbs wrote: > On 2025-06-23, rbowman <bowman@montana.com> wrote: > >> On Mon, 23 Jun 2025 01:01:45 -0400, c186282 wrote: >> >>> But yea, the universe rarely cooperates with 'logical' >>> systems humans might try to devise. Remember the old Greeks and their >>> obsession with 'perfect' circular motion in the cosmos ? The cosmos >>> was supposed to be 'divine', and therefore only 'perfect' geometry >>> would be seen. >> >> The universe laughs as humans invent arbitrary systems to explain it, and >> then pride themselves on how consistent their inventions are. > > Irrational numbers must drive those people nuts. They DO suck ... but, alas, MUST be dealt with. The universe isn't arranged for our convenience.
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-06-24 06:31 +0000 |
| Message-ID | <103dgnl$1rlr3$1@dont-email.me> |
| In reply to | #69071 |
On Tue, 24 Jun 2025 04:52:19 GMT, Charlie Gibbs wrote: > Irrational numbers must drive those people nuts. The Pythagoreans were horrified. Hippasus might have been killed to keep the fact secret.
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| From | The Natural Philosopher <tnp@invalid.invalid> |
|---|---|
| Date | 2025-06-24 10:19 +0100 |
| Message-ID | <103dqjr$1tngs$9@dont-email.me> |
| In reply to | #69049 |
On 23/06/2025 19:46, rbowman wrote: > On Mon, 23 Jun 2025 01:01:45 -0400, c186282 wrote: > >> But yea, the universe rarely cooperates with 'logical' >> systems humans might try to devise. Remember the old Greeks and their >> obsession with 'perfect' circular motion in the cosmos ? The cosmos >> was supposed to be 'divine', and therefore only 'perfect' geometry >> would be seen. > > The universe laughs as humans invent arbitrary systems to explain it, and > then pride themselves on how consistent their inventions are. Indeed it does. -- Microsoft : the best reason to go to Linux that ever existed.
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-06-24 22:25 +0000 |
| Message-ID | <103f8l9$29m22$3@dont-email.me> |
| In reply to | #69093 |
On Tue, 24 Jun 2025 10:19:55 +0100, The Natural Philosopher wrote: >> The universe laughs as humans invent arbitrary systems to explain it, >> and then pride themselves on how consistent their inventions are. > > Indeed it does. That’s a very ... um ... anthropomorphic mentality ...
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| From | rbowman <bowman@montana.com> |
|---|---|
| Date | 2025-06-25 02:02 +0000 |
| Message-ID | <mc13lqF6594U5@mid.individual.net> |
| In reply to | #69102 |
On Tue, 24 Jun 2025 22:25:45 -0000 (UTC), Lawrence D'Oliveiro wrote: > On Tue, 24 Jun 2025 10:19:55 +0100, The Natural Philosopher wrote: > >>> The universe laughs as humans invent arbitrary systems to explain it, >>> and then pride themselves on how consistent their inventions are. >> >> Indeed it does. > > That’s a very ... um ... anthropomorphic mentality ... It's the Zen catch-22. The chatter invented by humans is inadequate for expressing reality so you do the best you can.
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| From | c186282 <c186282@nnada.net> |
|---|---|
| Date | 2025-06-25 01:58 -0400 |
| Message-ID | <KeednUkPwP11Esb1nZ2dnZfqn_SdnZ2d@giganews.com> |
| In reply to | #69106 |
On 6/24/25 10:02 PM, rbowman wrote: > On Tue, 24 Jun 2025 22:25:45 -0000 (UTC), Lawrence D'Oliveiro wrote: > >> On Tue, 24 Jun 2025 10:19:55 +0100, The Natural Philosopher wrote: >> >>>> The universe laughs as humans invent arbitrary systems to explain it, >>>> and then pride themselves on how consistent their inventions are. >>> >>> Indeed it does. >> >> That’s a very ... um ... anthropomorphic mentality ... > > It's the Zen catch-22. The chatter invented by humans is inadequate for > expressing reality so you do the best you can. You've kind of GOT IT ... :-) It's NOT about us in the least.
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| From | c186282 <c186282@nnada.net> |
|---|---|
| Date | 2025-06-25 02:17 -0400 |
| Message-ID | <1i-dnVm-hLzDCcb1nZ2dnZfqn_UAAAAA@giganews.com> |
| In reply to | #69102 |
On 6/24/25 6:25 PM, Lawrence D'Oliveiro wrote: > On Tue, 24 Jun 2025 10:19:55 +0100, The Natural Philosopher wrote: > >>> The universe laughs as humans invent arbitrary systems to explain it, >>> and then pride themselves on how consistent their inventions are. >> >> Indeed it does. > > That’s a very ... um ... anthropomorphic mentality ... Actually, the OPPOSITE is. Sorry, bur it's NOT All About Us.
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| From | Charlie Gibbs <cgibbs@kltpzyxm.invalid> |
|---|---|
| Date | 2025-06-22 15:49 +0000 |
| Message-ID | <FCV5Q.1598985$G6Lf.181139@fx17.iad> |
| In reply to | #68996 |
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. -- /~\ Charlie Gibbs | Growth for the sake of \ / <cgibbs@kltpzyxm.invalid> | growth is the ideology X I'm really at ac.dekanfrus | of the cancer cell. / \ if you read it the right way. | -- Edward Abbey
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| From | rbowman <bowman@montana.com> |
|---|---|
| Date | 2025-06-22 19:09 +0000 |
| Message-ID | <mbr2nlF5ijfU2@mid.individual.net> |
| In reply to | #69009 |
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.
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| From | Charlie Gibbs <cgibbs@kltpzyxm.invalid> |
|---|---|
| Date | 2025-06-22 21:55 +0000 |
| Message-ID | <DZ_5Q.1372755$6%s6.27132@fx12.iad> |
| In reply to | #69011 |
On 2025-06-22, rbowman <bowman@montana.com> wrote: > We allowed users to configure the display values to decimal degrees, > minutes, or seconds as well as UTM and USNG but the values were stored as > double in decimal degrees. Your average dispatcher has no idea where any > of them are. I've written call accounting software for local 911 centres. The switches give us latitude and longitude in degrees with six decimals. That narrows it down to about 4 inches, which seems a bit optimistic, unless you somehow have access to a differential GPS setup. A friend who calibrated aeronautical navaids before he retired told me how they'd set up a differential GPS transmitter at an airport and get 1-centimeter accuracy while flying an approach. (Worst-case WAAS is 20 feet vertically, less horizontally - competitive with ILS.) Decimal degrees do make number crunching a lot easier. > If you want to have real fun with your Garmin set the datum to NAD27. > When he first started a geocacher was using that instead of WGS 84. The > coordinates were about 100 yards away, which is fun when you're looking > for a hidden ammo can on the side of a mountain. :-) -- /~\ Charlie Gibbs | Growth for the sake of \ / <cgibbs@kltpzyxm.invalid> | growth is the ideology X I'm really at ac.dekanfrus | of the cancer cell. / \ if you read it the right way. | -- Edward Abbey
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-06-23 02:25 +0000 |
| Message-ID | <103adv8$vun4$5@dont-email.me> |
| In reply to | #69013 |
On Sun, 22 Jun 2025 21:55:47 GMT, Charlie Gibbs wrote: > Decimal degrees do make number crunching a lot easier. Trig calculations are most easily done in radians. >> 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. That 100 yards sounds about right for the distance between Greenwich Observatory and the current location of the 0° longitude line ...
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| From | c186282 <c186282@nnada.net> |
|---|---|
| Date | 2025-06-23 01:07 -0400 |
| Message-ID | <NRWdnfz7XZ-JfMX1nZ2dnZfqnPednZ2d@giganews.com> |
| In reply to | #69020 |
On 6/22/25 10:25 PM, Lawrence D'Oliveiro wrote: > On Sun, 22 Jun 2025 21:55:47 GMT, Charlie Gibbs wrote: > >> Decimal degrees do make number crunching a lot easier. > > Trig calculations are most easily done in radians. > >>> 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. > > That 100 yards sounds about right for the distance between Greenwich > Observatory and the current location of the 0° longitude line ... That WILL keep drifting a bit, kinda forever .... The Earth is 'wobbly' and landmasses keep moving.
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| From | rbowman <bowman@montana.com> |
|---|---|
| Date | 2025-06-23 05:52 +0000 |
| Message-ID | <mbs8dhFbafcU3@mid.individual.net> |
| In reply to | #69020 |
On Mon, 23 Jun 2025 02:25:45 -0000 (UTC), Lawrence D'Oliveiro wrote: > On Sun, 22 Jun 2025 21:55:47 GMT, Charlie Gibbs wrote: > >> Decimal degrees do make number crunching a lot easier. > > Trig calculations are most easily done in radians. And getting to radians is a hell of a lot easier without having to beat degrees, minutes, and decimal seconds into a usable variable. > >>> 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. > > That 100 yards sounds about right for the distance between Greenwich > Observatory and the current location of the 0° longitude line ... https://www.australiangeographic.com.au/science-environment/2017/02/how- gps-keeps-up-with-australias-continental-drift I assume NZ is drifting around like an unmoored kayak too :) I don't know about GDA2020 but I think NGS 2022 got derailed by Covid 2020 and died a quiet death. https://ctgis.uconn.edu/wp-content/uploads/sites/2163/2018/05 /Datum_Changes_CT_GIS.pdf 6 or 7 years ago that was on my plate as a potential future problem since we dealt with the Department of Interior. Like all good things I procrastinated until the problem went away. https://www.esri.com/about/newsroom/arcuser/moving-from-static-spatial- reference-systems-in-2022
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| From | rbowman <bowman@montana.com> |
|---|---|
| Date | 2025-06-23 05:35 +0000 |
| Message-ID | <mbs7dgFbafcU2@mid.individual.net> |
| In reply to | #69013 |
On Sun, 22 Jun 2025 21:55:47 GMT, Charlie Gibbs wrote: > I've written call accounting software for local 911 centres. The > switches give us latitude and longitude in degrees with six decimals. > That narrows it down to about 4 inches, which seems a bit optimistic, > unless you somehow have access to a differential GPS setup. Back in the bad old days of K&E slide rules, even with magnifying cursors, you learned to do some sanity checking. Six decimal accuracy with consumer grade GPS receivers that have 5 to 10 meter accuracy on the best of days doesn't pass the sanity check. As AVL systems in the equipment became more prevalent we'd get a variety of formats, NMEA sentences being a popular one. https://w3.cs.jmu.edu/bernstdh/web/common/help/nmea-sentences.php Most of the USB hockey puck receivers spit them out and we'd wait for a GGA or RMC sentence. Years ago Trimble was a big player when emergency services started using AVL and they had their own format. Geocom, another player, sent the coordinated in hex. It's been a long time but there was also a magic number involved where x and y were the hex values. *lat = (double) x * 5.729577957 * .0000001; *lon = (double) y * 5.729577957 * .0000001; CalAmp sends a very proprietary struct with the values packed in big endian format. Great fun. Anyway, it all ended up as decimal degrees. Th job wasn't finished since most of the GIS data was in State Plane Coordinate System. https://en.wikipedia.org/wiki/State_Plane_Coordinate_System Like the article say, having Cartesian coordinates makes the math a lot easier. With spherical coordinates to find the distance from A to B you need to use the haversine or Vincenty's formula. https://en.wikipedia.org/wiki/Vincenty's_formulae Six decimal places in a double might imply accuracy that isn't really there, but you definitely don't want to try to cram it into a float and expect a happy ending when you start your conversions. > A friend > who calibrated aeronautical navaids before he retired told me how they'd > set up a differential GPS transmitter at an airport and get 1-centimeter > accuracy while flying an approach. > (Worst-case WAAS is 20 feet vertically, less horizontally - competitive > with ILS.) With DGPS, RTK, and post processing you can get the accuracy down to millimeters. I have a Amzfit Active 2 fitness watch that has a pretty good GPS. I'm amused by the posters on reddit complaining that they took an out and back hike and the two tracks aren't exactly on top of each other or doesn't show them on the sidewalk. They expect miracles from a $100 consumer device with a minimal patch antenna and also put a lot of trust in digital maps. I started using a GPS back in the '90s before Clinton took selective availability off. Even then it was a revelation. I was used to dealing with Forest Service maps of dubious accuracy and the notorious Forest Service miles that were even worse. It was amusing that what I had identified as Dead Skunk Point based on a crappy map and not knowing exactly where I was really wasn't Dead Skunk Point.
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| From | Charlie Gibbs <cgibbs@kltpzyxm.invalid> |
|---|---|
| Date | 2025-06-23 16:43 +0000 |
| Message-ID | <Xuf6Q.1622915$G6Lf.431992@fx17.iad> |
| In reply to | #69029 |
On 2025-06-23, rbowman <bowman@montana.com> wrote: > Years ago Trimble was a big player when emergency services started using > AVL and they had their own format. Geocom, another player, sent the > coordinated in hex. It's been a long time but there was also a magic > number involved where x and y were the hex values. > > *lat = (double) x * 5.729577957 * .0000001; > *lon = (double) y * 5.729577957 * .0000001; That number looks suspiciously like the number of degrees in a radian, divided by 10. > Six decimal places in a double might imply accuracy that isn't really > there, but you definitely don't want to try to cram it into a float and > expect a happy ending when you start your conversions. Many of the world's ills are caused by people using floating point when they really shouldn't. "Oh, there's a decimal in dollar amounts; that means we _must_ use floating point." They obviously never heard of decimal pennies (or suitable fractions of pennies). Mind you, early BASICs with 16-bit integers encouraged the belief... -- /~\ Charlie Gibbs | Growth for the sake of \ / <cgibbs@kltpzyxm.invalid> | growth is the ideology X I'm really at ac.dekanfrus | of the cancer cell. / \ if you read it the right way. | -- Edward Abbey
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| From | rbowman <bowman@montana.com> |
|---|---|
| Date | 2025-06-23 19:11 +0000 |
| Message-ID | <mbtn7fFjbqdU3@mid.individual.net> |
| In reply to | #69038 |
On Mon, 23 Jun 2025 16:43:35 GMT, Charlie Gibbs wrote: > On 2025-06-23, rbowman <bowman@montana.com> wrote: > >> Years ago Trimble was a big player when emergency services started >> using AVL and they had their own format. Geocom, another player, sent >> the coordinated in hex. It's been a long time but there was also a >> magic number involved where x and y were the hex values. >> >> *lat = (double) x * 5.729577957 * .0000001; >> *lon = (double) y * 5.729577957 * .0000001; > > That number looks suspiciously like the number of degrees in a radian, > divided by 10. You're right. I was looking at source code I wrote about 20 years ago without giving it much thought. Unfortunately, now I'm thinking. I wonder what the raw GNSS data looks like? There are a lot of GPS modules for microprocessors but afaik they only spit out NMEA sentences. That's no fun.
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-06-24 01:36 +0000 |
| Message-ID | <103cveo$1jvc7$4@dont-email.me> |
| In reply to | #69038 |
On Mon, 23 Jun 2025 16:43:35 GMT, Charlie Gibbs wrote: > Many of the world's ills are caused by people using floating point when > they really shouldn't. "Oh, there's a decimal in dollar amounts; > that means we _must_ use floating point." They obviously never heard of > decimal pennies (or suitable fractions of pennies). Remember that, in the current IEEE 754 spec, floating-point can be decimal or binary. Very few languages include fixed-point types (with a fractional part) as standard -- Ada being an exception, as I recall.
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| From | Charlie Gibbs <cgibbs@kltpzyxm.invalid> |
|---|---|
| Date | 2025-06-24 04:52 +0000 |
| Message-ID | <aaq6Q.21563$9SBb.2907@fx18.iad> |
| In reply to | #69062 |
On 2025-06-24, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
> On Mon, 23 Jun 2025 16:43:35 GMT, Charlie Gibbs wrote:
>
>> Many of the world's ills are caused by people using floating point when
>> they really shouldn't. "Oh, there's a decimal in dollar amounts;
>> that means we _must_ use floating point." They obviously never heard of
>> decimal pennies (or suitable fractions of pennies).
>
> Remember that, in the current IEEE 754 spec, floating-point can be decimal
> or binary.
>
> Very few languages include fixed-point types (with a fractional part) as
> standard -- Ada being an exception, as I recall.
Meanwhile we have to fake it:
printf("%8ld.%02d\n", amount / 100L, amount % 100L);
Handling negative amounts is left as an exercise for the user.
Don't knock integer pennies - you'll have a horde of accountants
on your back if you lose track of pennies in large amounts.
--
/~\ Charlie Gibbs | Growth for the sake of
\ / <cgibbs@kltpzyxm.invalid> | growth is the ideology
X I'm really at ac.dekanfrus | of the cancer cell.
/ \ if you read it the right way. | -- Edward Abbey
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| From | Lawrence D'Oliveiro <ldo@nz.invalid> |
|---|---|
| Date | 2025-06-24 06:47 +0000 |
| Message-ID | <103dhmr$1rlr3$2@dont-email.me> |
| In reply to | #69074 |
On Tue, 24 Jun 2025 04:52:22 GMT, Charlie Gibbs wrote:
> On 2025-06-24, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
>
>> Very few languages include fixed-point types (with a fractional part)
>> as standard -- Ada being an exception, as I recall.
>
> Meanwhile we have to fake it:
>
> printf("%8ld.%02d\n", amount / 100L, amount % 100L);
>
> Handling negative amounts is left as an exercise for the user.
Some languages don’t need to “fake” it:
import decimal as dec
from decimal import \
Decimal
D = Decimal
DECIMALS = 2
def fmt(d : Decimal) :
# returns string representation of d with DECIMALS decimal places
if isinstance(d, Decimal) :
pass
elif isinstance(d, int) :
d = D(d)
else :
raise TypeError("arg must be of Decimal type")
#end if
if d < 0 :
sign = "-"
d = - d
else :
sign = ""
#end if
s = str(int(round(d, DECIMALS) * D('10') ** DECIMALS))
if len(s) > DECIMALS :
s = s[:len(s) - DECIMALS] + "." + s[len(s) - DECIMALS:]
else :
s = "0." + ("0" * (DECIMALS - len(s))) + s
#end if
return sign + s
#end fmt
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| From | c186282 <c186282@nnada.net> |
|---|---|
| Date | 2025-06-24 01:02 -0400 |
| Message-ID | <fUednafSpfTArMf1nZ2dnZfqnPednZ2d@giganews.com> |
| In reply to | #69062 |
On 6/23/25 9:36 PM, Lawrence D'Oliveiro wrote: > On Mon, 23 Jun 2025 16:43:35 GMT, Charlie Gibbs wrote: > >> Many of the world's ills are caused by people using floating point when >> they really shouldn't. "Oh, there's a decimal in dollar amounts; >> that means we _must_ use floating point." They obviously never heard of >> decimal pennies (or suitable fractions of pennies). > > Remember that, in the current IEEE 754 spec, floating-point can be decimal > or binary. > > Very few languages include fixed-point types (with a fractional part) as > standard -- Ada being an exception, as I recall. Ada does. However you're very right, very FEW langs these days include fixed-point as standard, or at all. Maybe it's just because most everything now has float support, or maybe everyone has FORGOTTEN why fixed was useful. Maybe I need to brush up on my COBOL .........
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