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Does anyone know any trig tricks for gradients or azimuths.

freed2003 wrote:Does anyone know any trig tricks for gradients or azimuths.

There are 2 types of gradients
- Road gradient = Change in elevation / Distance * 100 ft
- Stream gradient = Change in elevation / Distance * 1000ft

Azimuth is a heading direction between 2 points in 360 degree starting from True north. Normally a protractor can be used to measure the heading. But if you want to get fancy, you can buy the military azimuth protractor where you can use to measure the heading angle., something like this on e-bay. http://www.ebay.com/itm/RM-PRODUCTS-RM- ... SwP~tW3Dk3

By trig I meant trigonometry, I assume the tan function could be useful

freed2003 wrote:By trig I meant trigonometry, I assume the tan function could be useful

Yes for Gradients, (Depending on what values are given e.g: straight line distance, land distance, hight difference)

Trig is not so helpful for azimuth

what about arctan?

It's been a while since I've competed in Road Scholar, but I'm not sure how much extra time you'd be saving by using trig to calculate azimuths or gradients. With gradients, you will still have to measure the distance between the two points, unless the question gives you the angle, and due to the small angle approximation, the angle becomes the gradient regardless.

Azimuths are probably more suited for trig, if you measure the coordinates using UTM, and then take . However, since the arctan function is limited in range, you'll have to add 180 degrees if the azimuth direction is to the southeast/southwest, or 360 degrees if it's to the northwest. Personally, I feel like using one of these bad boys is easier: (image from amazon)


Trig is a really useful thing to use. However, test-makers will be making the tests knowing that most competitors will probably not know trig. Also (for azimuths especially), using the conventional method likely leads to a fuller understanding of what you're actually calculating, so for anyone else who's reading this, I would recommend not trying to use a trig shortcut unless you're already very comfortable and familiar with the concepts behind it. Of course, it's possible there's an easier method to use trig than either of those I've put here, and as long as the method gets you the answer, there's no harm done. I just don't recommend this to other people who may not be as experienced in the event.

EastStroudsburg13 wrote: Trig is a really useful thing to use. However, test-makers will be making the tests knowing that most competitors will probably not know trig. Also (for azimuths especially), using the conventional method likely leads to a fuller understanding of what you're actually calculating, so for anyone else who's reading this, I would recommend not trying to use a trig shortcut unless you're already very comfortable and familiar with the concepts behind it. Of course, it's possible there's an easier method to use trig than either of those I've put here, and as long as the method gets you the answer, there's no harm done. I just don't recommend this to other people who may not be as experienced in the event.

I total agree. This is div B events where most 6-9 graders HAVE NOT been exposed to trig yet. Keep in simple, just measure the distant and change in elevation, then multiply by either 100 or 1000 depending on whether it's road gradient or stream gradient

How do other people do practice tests? I can't seem to find the maps.

freed2003 wrote:How do other people do practice tests? I can't seem to find the maps.

You can download topo maps here: http://nationalmap.gov/ustopo/index.html Printing them at a high enough resolution to be useful may or may not be possible at your school, but I imagine Kinko's or Staples etc could do it. If your team participates in any invitationals, it's possible that you'll be allowed to take the map home. I was lucky enough to grab a handful of different maps at a coaches' conference last year which my students use to generate their own questions for their partners to quiz on.