Post AdW7OcOHEawB2ilFSq by attie@chaos.social
 (DIR) More posts by attie@chaos.social
 (DIR) Post #AdW7OcOHEawB2ilFSq by attie@chaos.social
       2024-01-04T22:01:18Z
       
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       Please help me name a unit, or find an existing prefix.NMEA provides longitude / latitude as Degrees and Arc Minutes (to 5 decimal places) - a resolution of approx 1.11m at the equator.This will translate nicely into an int32_t with units of 1e-5 arc minutes per LSB (i.e: 10 μam per LSB).What to we call 1e-5 arc minutes?... calling it 10μam feels boring, but that's where I'm currently headed.e.g:51°15.81498' N, 2°8.81592' Wbecomes+307,581,498 / -12,881,592https://maps.app.goo.gl/2uABzBLRgtdtGU3W7
       
 (DIR) Post #AdW7OdXswMDWcoGR4y by attie@chaos.social
       2024-01-04T23:03:13Z
       
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       I think I'm settling on just referring to it as "10 μam"... I wanted to avoid confusion around "am I supposed to multiply this value by 10, or not"... but I think (hope) it'll hold together okay with worked examples.
       
 (DIR) Post #AdW7OeLrwWCR7peLzM by penguin42@mastodon.org.uk
       2024-01-04T23:08:16Z
       
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       @attie You realise it's probably dangerously close to a fathom; https://en.wikipedia.org/wiki/Fathom
       
 (DIR) Post #AdW7ed9k9iKq3CbAAq by attie@chaos.social
       2024-01-04T23:11:08Z
       
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       @penguin42 10μam is ~1.11m at the equator (getting smaller towards the poles), so about 60% or less than a fathom! 🙈
       
 (DIR) Post #AdWAjstnLrOUBcKrcO by penguin42@mastodon.org.uk
       2024-01-04T23:45:43Z
       
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       @attie Which makes you wonder if the reason for that NMEA precision is so that they have a precision of at least a fathom, I mean the M in NMEA is marine.
       
 (DIR) Post #AdWAwdh3CGCKn9SM4W by attie@chaos.social
       2024-01-04T23:47:59Z
       
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       @penguin42 Could be! Though the DOP may be related too (i.e: GPS is often able to give better than ~11m, but not better than ~1.1m).https://en.wikipedia.org/wiki/Decimal_degrees#Precision
       
 (DIR) Post #AdWCQcUUKflvhgRLlY by penguin42@mastodon.org.uk
       2024-01-05T00:04:41Z
       
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       @attie Either that or Roman horses.