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Why an Azimuth

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Why an Azimuth?

An azimuth is defined as a horizontal angle measured clockwise from a north base line. This north base line could be true north, magnetic north, or grid north. The azimuth is the most common military method to express direction. When using an azimuth, the point from which the azimuth originates is the center of an imaginary circle (Figure 6-2). This circle is divided into 360 degrees or 6400 mils (Appendix G).

Clear as mud, huh? Let me help.

If I were standing in a parking lot, and wanted to go directly to a lamp post I could see, I would pick a straight line, and just walk there. You might call that straight line an azimuth.

If there were a Library at the top of the parking lot, or right in front of me, we might imagine that as North. We could figure out, by drawing on the parking lot, the difference between a straight line to the Library and a straight line to the lamp post. That would be expressed in degrees, like the degrees of a circle. We might walk a forty degree azimuth to the lamp post.

Now, lets “jazz up” the parking lot. Let’s put a mountain, some trees, and a stream in it. Now, we can’t really see the lamp post, from all points in the parking lot.

If the Library were one-hundred stories, you could see it from anywhere, even in our jazzed up parking lot. We can not see the North Pole, but a compass always points there. The example is the same.

Our lamp post is on a line that is forty degrees to the right of the line that is directly to the Library. The azimuth to the lamp post is forty degrees.

If you keep walking the same angle you determined the lamp post to be, in relation to the Library, down around the Mountain base and through the river in our jazzed up parking lot, you would wind up somewhere in the area of where the lamp post is, if not directly on it. Even if you got turned around, by facing the Library, and pointing to the pre-determined angle, you should find the lamp post, or be going towards it.

By the same example, I can not see Chicago. If I located myself on a map that showed both me and Chicago, and drew a line between them, I would have my direction of travel. I could take a protractor and measure the difference between the direction of travel and “straight up” on the map.

By keeping my compass pointing North and walking along that direction of travel, or azimuth, I would eventually wind up in Chicago, or close to it.

Addenda: Most people, when they teach, “gloss over” some points. In some cases, True North, Grid North, and Map North are not the same. We do not need to discuss that for teaching purposes. Most of us will never use anything but magnetic north, for hiking, anyway. We are not cartographers, or map makers. If you get anything at all from what I write, try to find the main point, and learn that. Other, finer detail will follow, if needed. You gotta take one step at a time.