Reverse Azimuth help?

[+fizzgigg]

I was wondering if I could get a little help. A cache I would like to look for on an upcoming road trip has this in it's description:

 

The cache is located 408 feet away at a reverse azimuth of 298°

 

1st - how do I measure a reverse azimuth? I am using a flat, plastic, classic compass since my eTrex Legend Cx does not have a real compass. I've looked the definition up online and now I'm more confused than ever. (I don't know if I even know how to pronounce azimuth!)

 

2nd - does anyone have any tips for how to best measure feet traveled using their GPSr?

 

I think I'm getting too bogged down in the details, not seeing the forest for the trees, etc. with this problem. I've found 2 caches where you locate point A, take a heading of X degrees, walk Y feet. I was lucky in both instances and had to stop when I reached Y feet because there was a building or hedge or somesuch where the cache was hidden.

 

Thanks in advance!

[+andGuest]

To go in a reverse azimuth you either add of subtract 180 degrees to the posted coordinates (whichever will give you a number between 0 and 360 degrees) and that degrees is your reverse azimuth bearing.

To figure the distance just have you GPS on the posted (known) coordinate and walk the reverse azimuth as stated. It will count the feet for you just counting up instead of down.

If for some reason that does not work you can figure out your pace count for a known distance. Simply measure out a known distance (100 feet, 100 yards, 100 meters) that is applicable to your situation. Now walk that distance counting every time you take a step or take a step with whichever foot. Then you know your pace count for that distance. Now use simple mathematics to figure out the number of steps you need to take.

For example in your post it said to go 408 feet and say it takes you 33 steps to go 100 feet:

 

Therefore you must go 33 steps 4.08 times (408/100); so 33 X4.08 = 134.64 (135) steps

 

Hope this helps and doesn't confuse. If you were looking for caches without a GPS this is how you would find them. Find a landmark, get a bearing and distance and pace from said landmark to the cache.

[+bwmick]

if the legend has a projection feature it will make the job real easy. do the math on the reverse azimuth and then tell the legend to project a waypoint enter the bearing and distance and give the projected waypoint a name you will remember than enter. next find waypoint (you name it you find it) and follow the arrow. I did a multi last week that required me to project 5 times. I was glad I remembered how it worked.

[+edscott]

I was wondering if I could get a little help. A cache I would like to look for on an upcoming road trip has this in it's description:

 

The cache is located 408 feet away at a reverse azimuth of 298°

 

1st - how do I measure a reverse azimuth? I am using a flat, plastic, classic compass since my eTrex Legend Cx does not have a real compass. I've looked the definition up online and now I'm more confused than ever. (I don't know if I even know how to pronounce azimuth!)

 

2nd - does anyone have any tips for how to best measure feet traveled using their GPSr?

 

I think I'm getting too bogged down in the details, not seeing the forest for the trees, etc. with this problem. I've found 2 caches where you locate point A, take a heading of X degrees, walk Y feet. I was lucky in both instances and had to stop when I reached Y feet because there was a building or hedge or somesuch where the cache was hidden.

 

Thanks in advance!

 

You can do the math described elewhere if you want, or do what I do and simply put the WHITE end of the needle on N and go for it. First crank the compass housing to 298 degrees. Then add or subract whatever your local declination is if you need real accuracy.. in 400 feet the difference won't be a whole lot. Reverse the compass so the white end of the needle is pointing north and take about 143 full steps in the direction of the directional arrow on the compass baseplate.

Edited August 23, 2007 by edscott

[+fizzgigg]

Thanks everyone! I'm pretty sure that I understand now and I was making it much more difficult than it needed to be.

 

Hopefully, by lunchtime tomorrow I'll have another smiley to add to my list.

[+Papafuz & Mama]

I was wondering if I could get a little help. A cache I would like to look for on an upcoming road trip has this in it's description:

 

The cache is located 408 feet away at a reverse azimuth of 298°

 

1st - how do I measure a reverse azimuth? I am using a flat, plastic, classic compass since my eTrex Legend Cx does not have a real compass. I've looked the definition up online and now I'm more confused than ever. (I don't know if I even know how to pronounce azimuth!)

 

2nd - does anyone have any tips for how to best measure feet traveled using their GPSr?

 

I think I'm getting too bogged down in the details, not seeing the forest for the trees, etc. with this problem. I've found 2 caches where you locate point A, take a heading of X degrees, walk Y feet. I was lucky in both instances and had to stop when I reached Y feet because there was a building or hedge or somesuch where the cache was hidden.

 

Thanks in advance!

 

Here's how to reverse an azimuth; If the heading is less than 180', add 180'. If the heading is more than 180' subtract 180'. for instance, the reverse of 298' is 118'. A heading and an azimuth is the same thing. Hope this helps

Edited August 24, 2007 by Papafuz

[+Formerly Dominoes]

The cache is located 408 feet away at a reverse azimuth of 298°

 

If you leave your point A waypoint loaded in your GPS. head off on a bearing of 118° (your reverse azimuth). When your GPS says that you are 408 feet, bearing 298. You are at point B.

 

This is how I used to do it with my old Explorist 200. My new Legend C can project a waypoint, but I still use this technique, as it saves time.

[+babama]

From what I have read here, you should get in the right area. Finding the cache is going to be a bit tougher though. I know this cache, it is about 10 mi. from my house, and took me two trips to get it. If you need any more help with it, shoot me an email. I will help you as much as I can without giving away the cache.

[+edscott]

From what I have read here, you should get in the right area. Finding the cache is going to be a bit tougher though. I know this cache, it is about 10 mi. from my house, and took me two trips to get it. If you need any more help with it, shoot me an email. I will help you as much as I can without giving away the cache.

 

If he is still looking for it you should go in with some food and maybe a body bag... been almost 6 months.

[+Rattlebars]

The cache is located 408 feet away at a reverse azimuth of 298°

 

If you leave your point A waypoint loaded in your GPS. head off on a bearing of 118° (your reverse azimuth). When your GPS says that you are 408 feet, bearing 298. You are at point B.

 

This is how I used to do it with my old Explorist 200. My new Legend C can project a waypoint, but I still use this technique, as it saves time.

 

Would that not be "head off on a HEADING of 118°"?

 

My understanding is that a HEADING is the azimuth on which you ARE CURRENTLY traveling and BEARING is the azimuth on which you SHOULD be traveling to get to a point. When moving toward a known waypoint, the closer your HEADING is to the BEARING (the difference being the cross track error), the faster you'll get there.

 

The simplest way to do a reverse azimuth from a known waypoint would be to leave (or set if you haven't already got it as your goto) that waypoint as the destination then HEAD in a direction which will cause your GPSr to show a BEARING of 298° as you travel away from it. Once the GPSr shows 408ft from the waypoint, start looking.

 

It is important to know if Magnetic or True North is used for reference. My rule of thumb is if the cache page does not specifically state that it is Magnetic North, I use True north. You can be quite a bit off if you are using Magnetic without a declination adjustment when you should be using True.

 

Someone will correct me if I'm wrong.