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Full Version: HP-35A/21 D.MS<-->Decimal degrees routines
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Hello all,

In that the HP-21 (Woodstock) and HP-35 (Classic) do not have conversions to and from degrees to degrees/minutes/seconds, has anyone devised a method to convert the decimal degree value to degrees-minutes-seconds? Please let me know.

Thanks

Edited: 28 Mar 2012, 8:50 p.m.

Not anything automatic. You can obviously do it by working through the calculations manually.

From Hewlett-Packard's HP-35 MATH PAC, available in the HP Museum DVD 1, Calculator Manuals:

```Degrees, minutes and seconds to decimal degrees
LINE	DATA	OPERATIONS		DISPLAY		REMARKS
1    Seconds	ENTER^ 6 0 STO /
2    Minutes   + RCL /
3    Degrees   +
Example
32.6      ENTER^ 6 0 STO /     .5433333333
17       + RCL /              .2923888888
46       +                    46.29238889       46°17'32.6" = 46.29°

Decimal degrees to degrees, minutes and seconds
LINE	DATA	OPERATIONS		DISPLAY		REMARKS
1       X	ENTER^                                  Let D = integer part of X
2       D                              Degrees
3              - 6 0 STO *                A            Let M = integer part of A
4       M                              Minutes
5              - RCL *                    B            Let S = nearest integer to B
6       S                              Seconds

Example
23.32916667	ENTER^                  23.32916667
23                               23.             Degrees (integer part of X)
- 6 0 STO *              19.7500002
19                               19.             Minutes (integer part of X)
- RCL *                  45.000012
45                               45              Seconds (nearest integer to X)
23.32916667° = 23°19'45"```

Quote:
```LINE	DATA	OPERATIONS		DISPLAY		REMARKS
1    Seconds	ENTER^ 6 0 STO /
2    Minutes   + RCL /
3    Degrees   +```

Interesting, using the single storage register and saving no keystrokes in doing so....

Likewise for the reverse conversion.

- Pauli

Edited: 28 Mar 2012, 10:54 p.m.

There was a tread not too long ago where somebody posted equations that accomplish this. He made his posting as a guessing game, something about "Try to identify these" or something like that. I did a quick search, but came up empty handed. Does this ring any bells?

Very respectfully,

David

Here it is:

Regards,

Gerson.

Quote:
Interesting, using the single storage register and saving no keystrokes in doing so....

...unless more than one conversion is performed, but then the instructions should be updated:

```LINE	DATA	OPERATIONS		DISPLAY		REMARKS
1    Seconds	ENTER^ 6 0 STO /                        for the second and subsequent conversions
ENTER^ RCL /
2    Minutes   + RCL /
3    Degrees   +```

Gerson.

Edited: 29 Mar 2012, 7:52 a.m.

RCL should make ENTER^ superfluous.

Hello all. Fantastic job on the D.MS<-->D.DDD conversion routines. I tried developing some algorithms last night. In comparison, yours were quite streamlined.

Right you are! This means more keystroke saving on multiple conversions. I guess surveyors appreciated the successor of the HP-35, the HP-45, when it was released.
Still not programmable, but it had ->D.MS and D.MS-> built-in :-)

Also, a nice feature: no matter the current display mode, ->D.MS would leave the calculator temporarily in FIX 4 mode.

Edited: 29 Mar 2012, 2:12 p.m.