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Azimuth or Bearing

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Skills4Survival:
I have been struggling to understand the difference between Azimuth and Bearing, not even knowing how to call it in dutch to be honest, nor have I really researched it, I use..translated, "angle of direction" or in Dutch "richtingshoek". In the book, on page 17, I want to quote: "Azimuth: the azimuth is taken to mean the horizontal angle of a bearing clockwise from north."  What that means I do not fully understand. For  me...I "believe" in the following..in the context of land navigation (context is important)

1. Azimuth is used with a true north reference only
2. Azimuth is used clockwise only
3. Bearing can have other references then true north and simple depicts the angle from a viewpoint between Point A and B, using a reference line of north, east, south, west. Syntax would be like this. E 45 E. Reference is East (90) + add 45 degrees.
4. Bearing can only go to 90 degrees max, azimuth is between 0-360. In the previous example the azimuth would be East, being 90 degrees + 45 = 135 degrees.

My questions:
- is the quotation simple saying that azimuth and bearing are actually the same?
- would the four above statements make sense to use as a guideline? Or..is it maybe symantics only and just a difference which exist in usage between e.g. countries like U.K and U.S.A? (when taking the context of land navigation into account?)
- Taking it further, we have different types of bearing, would a "true bearing" be the same as an azimuth?

Any thoughts / comments / answers ?

thanks, Ivo


Pete McK:
Hi Ivo and welcome to the community :)

I read Astronomy at Uni so although relatively new to navigation feel somewhat qualified to answer some of your questions.

The scientific definition of azimuth is that it represents an angular measurement in a spherical coordinate system and obviously when used in astronomy can be used to measure of the position of a star in the night sky where the reference plane is the horizon and the reference vector points to the north. The azimuth is the angle between the north point and the perpendicular projection of the star down onto the horizon.

Luckily, in land navigation we only work in one plane, and the word has become familarised to represent a bearing: they are synonymous - so just substitute the word azimuth for bearing.

The word is much more frequently used by American navigators, in particular their military.

Hope this helps :)

Skills4Survival:
Yes ! Thank you.

Pete McK:
Your welcome Ivo :)

Living in Holland I guess you may have travelled to Germany quite a few times and wondered if you have come across any of the 400 degree compasses the UNM refers to? They seem to make more sense than the conventional 360.

Plus, does anyone know why we use 360?

sniperkona:
http://en.wikipedia.org/wiki/Degree_(angle)

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