Is there a way to work with angles in DMS without converting them to decimal degrees, that is to sum them, subtract them?
I do not know how to even enter it without using string. My idea is something like: 20°32'15.828'' - 22°32'12.8''.
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You may use either MixedRadixQuantity or Quantity with MixedMagnitude and MixedUnit.
In both cases the units you need are {"AngularDegrees", "ArcMinutes", "ArcSeconds"}.
p1 = MixedRadixQuantity[{20, 32, 15.828}, {"AngularDegrees", "ArcMinutes", "ArcSeconds"}];
p2 = MixedRadixQuantity[{22, 32, 12.8}, {"AngularDegrees", "ArcMinutes", "ArcSeconds"}];
p1 - p2
(* Quantity[MixedMagnitude[{-1, -59, -56.972}],
MixedUnit[{"AngularDegrees", "ArcMinutes", "ArcSeconds"}]] *)
From the output above you can see the longer form using Quantity.
Hope this helps.
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1$\begingroup$ OK, I guess +1 for technical correctness, but...OMG...it's worse than COBOL. :) $\endgroup$ – Michael E2 Aug 27 '16 at 23:04
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$\begingroup$ @MichaelE2 Of course a helper function can be used:
dms=MixedRadixQuantity[#, {"AngularDegrees", "ArcMinutes", "ArcSeconds"}]&$\endgroup$ – Edmund Aug 27 '16 at 23:14 -
1$\begingroup$ I suppose it's clear that I'm complaining about M, not your answer. I think carrying around these large, slow data structures internally is a waste. It's ok for UI purposes, although in this case, the formatted output is not highly readable. $\endgroup$ – Michael E2 Aug 27 '16 at 23:23
