Q:Why is the direction designated by S22°30′E not commonly used in the US?

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Discussion Overview

The discussion revolves around the designation of compass directions, specifically the notation S22°30′E, and its usage in navigation. Participants explore the historical context of compass divisions, the interpretation of bearings, and the differences in terminology used in various navigation practices.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants seek clarification on the meaning of "two points" in relation to compass directions, specifically how it relates to S22°30′E.
  • There is a question about whether S22°30′E means 22 degrees and 30 minutes east from due south, with some participants affirming this interpretation.
  • One participant notes that the compass was historically divided into 32 points, each representing 11.25 degrees.
  • Another participant raises the ambiguity of the bearing S22°30′E compared to 22°30′ SE, questioning how degrees are calculated from due south.
  • Concerns are expressed about the unfamiliarity of the notation S22°30′E among some navigators, with suggestions that it may not be commonly used in the U.S.
  • Participants discuss the potential confusion in interpreting bearings and the importance of clarity in navigation terminology.
  • Some participants reference external sources, including Wikipedia, to support their points about navigation and compass usage.
  • There is mention of the differences in practices between military navigation and civilian surveying, with a focus on the use of azimuth and grid systems in the Army.

Areas of Agreement / Disagreement

Participants express varying levels of familiarity with the notation S22°30′E, with some agreeing on its interpretation while others remain uncertain. There is no consensus on its commonality in U.S. navigation practices, indicating multiple competing views.

Contextual Notes

Participants highlight the historical context of compass usage and the potential for confusion in modern applications. The discussion reflects a range of experiences and knowledge levels regarding navigation terminology.

jackson6612
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The linked picture shows a compass rose showing the four cardinal directions, the four ordinal directions, plus eight further divisions.

Picture:
http://en.wikipedia.org/wiki/File:Brosen_windrose.svg

south-southeast
a compass point that is two points east of due south : S22°30′E
[M-W Col. Dic.]

Q1:
I couldn't understand the 'two points' part. Please help me with it.

Q2:
I also didn't understand the direction designated by S22°30′E. A compass is divided into 360 degrees. Does it mean 22 degrees and 30 minutes in the direction of east from due south? It would be kind of you if you can help me with it.

Thank you, in advance.
 
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In the old days the compass was divided into 32 points of 11 1/4 degrees.
 
Thanks, AC.

Here is a 32-points compass:
http://smsmoewe.com/pics/comprose.gif
http://smsmoewe.com/sundry/smsmhd01.htm

Q1:
Does it mean by two points M-W meant first point 'S' and the second point 'S by E'? This makes SSE two points away of due S.

Q2:
Is S22°30′E the same as 22°30′ SE? If it is, would the degrees be calculated from due S?

Please help me with the above questions.
 
The table you linked to has
south southeast 157.50°
That is, 22.50° (or two points = 2 x 11.25°) east of due south (180°). The first letter in the bearing is either due north or due south.

The "bearing" you quoted 22°30' SE is ambiguous. Is it 22°30' east of SE or south of SE? That's why the bearing is built the way it is.
 
jackson6612 said:
Thanks, AC.

Here is a 32-points compass:
http://smsmoewe.com/pics/comprose.gif
http://smsmoewe.com/sundry/smsmhd01.htm

Q1:
Does it mean by two points M-W meant first point 'S' and the second point 'S by E'? This makes SSE two points away of due S.

Q2:
Is S22°30′E the same as 22°30′ SE? If it is, would the degrees be calculated from due S?

Please help me with the above questions.

Where did this quote come from? I've never seen "S22°30′E" before, and I was a (admitedly Air Force) navigator, but it does seem it would follow the pattern "south by southeast" not "22°30′ SE" or even 22°30′ south of east. So the most likely interpretation is 157.5° as in the preceding post by dulrich.
 
Thanks a lot, Dulrich.

The first letter in the bearing is either due north or due south.

Do you mean to say that the bearing of due west is quoted as N90°W, or S90°W?
 
dulrich said:
I hope I haven't overstepped the limit of my ignorance as I'm not really an expert in navigation, etc. But the following wikipedia article does use the example of a bearing of N 60° E:

http://en.wikipedia.org/wiki/Bearing_(navigation)#Land_navigation

As far as due west, I would guess that an exception is made and it's simply called due west. Here's another link I found ala Google:

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/comp.html

So in the early days of navigation we have the 32 points, which probably means the helmsman could only hold a heading plus/minus 5 degrees. At first I thought this would lead to a problem with celestial fixes; but the astrolabe only does altitude of the object anyway, which still provides a position fix.

You do need something more accurate for surveying (thanks, dulrich). You would have a fixed card with 360 ticks, probably without numbers assigned and a north-south needle. Easiest way to read this is the number of degrees from the nearest head/tail of the needle. First thing you write down is whether it's the north end or the south end, then you read off the number of degrees east or west of that.
 
Where did this quote come from? I've never seen "S22°30′E" before, and I was a (admitedly Air Force) navigator, but it does seem it would follow the pattern "south by southeast" not "22°30′ SE" or even 22°30′ south of east. So the most likely interpretation is 157.5° as in the preceding post by dulrich.

Hi AC

The quote come from M-W's Collegiate Dictionary as I mentioned in the start of this thread.

I don't know the reason why you haven't ever seen "S22°30′E" before. Perhaps, you are making a point that the bearing SSE is not written this way as far as you can tell, or you could be concerned about the format "S...E". If it's the former, the dictionary is simply defining, explaining where that point is located on the compass. If the latter, it's my general view that bearing is mostly written this way - e.g. check this link quoted by Dulrich: http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/comp.html

Thank you for all the help. Please correct me if I'm wrong.
 
  • #10
jackson6612 said:
Hi AC

The quote come from M-W's Collegiate Dictionary as I mentioned in the start of this thread.

I don't know the reason why you haven't ever seen "S22°30′E" before. Perhaps, you are making a point that the bearing SSE is not written this way as far as you can tell, or you could be concerned about the format "S...E". If it's the former, the dictionary is simply defining, explaining where that point is located on the compass. If the latter, it's my general view that bearing is mostly written this way - e.g. check this link quoted by Dulrich: http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/comp.html

Thank you for all the help. Please correct me if I'm wrong.

Other than surveying (I haven't located my book on that, a passing fancy years ago), I do not believe "S22°30′E" is used anywhere in the U.S. That would include land navigation, which I had a course in during survival training. The Army likes to use a grid system for coordinates for coordinates, but definitely uses 360 degree azimuth for bearing.

I still have an Army "lensamatic" hand compass. It has a "floating" card, which is to say the whole thing turns; it doesn't have a needle. It is marked with N-E-S-W and 360-degree azimuth; "S22°30′E" would be awkward to read requiring subtraction and thereby inducing errors.

I do not know how surveying transits are marked. Surveyors do tend to hold on to old traditions.
 
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