Finding Utm

[DrWongAndTheMoppets]

How can I determine the location N XX° XX.XXX W XXX° XX.XXX of a cache when I have the bearing (XXXº True) and the distance (XXX meters) from current location.

 

example: from N 49° 15.512 W 122° 47.158 head 100 meters at a bearing of 330º

 

What is the cache location?

[Bobthearch]

First you would have to translate the Longitude-Latitude coordinates to UTMs. Then you would have to use some serious geometry to figure in the angle and distance. Then you have to find the relative grid location and adjust the original UTM numbers appropriately.

 

Why not just shoot a compass bearing and pace off 100 meters?

 

Best Wishes,

Bob

[DrWongAndTheMoppets]

I more or less assumed that using a compass was the best way, but I have been trying to find out if it could be done by using a calculation also.

 

If it involves so called "serious geometry" than it is not something that I would be wise to attempt.

 

thanks bob

[+Stunod]

First of all, set your GPS up to give distance in meters.

 

If your GPS has a "project waypoint" function, you can go to the coords, and Project a new waypoint 100m away at 330 degrees.

 

OR

 

Program a waypoint for the given coords...then move to a position that has your GPS showing that waypoint 100meters away at a bearing of 150 degrees (180 degress from the given 330).

[Bobthearch]

As a archaeologist I've found, recorded, and mapped hundreds (thousands?) of previously undocumented arch sites. In nearly every instance the maps are drawn by shooting compass bearings and pacing. With a little practice it can be very accurate, and certainly accurate enough for Geocaching.

 

When I say "serious geometry" I mean ~maybe~ I could do it by sketching it on paper and taking a refresher course. It's not rocket science, but it's a lot closer than what I'm used to.

 

Best Wishes,

Bob

[+PDOP's]

How can I determine the location N XX° XX.XXX W XXX° XX.XXX of a cache when I have the bearing (XXXº True) and the distance (XXX meters) from current location.

 

example: from N 49° 15.512 W 122° 47.158 head 100 meters at a bearing of 330º

 

What is the cache location?

GeoClac will do this.

[+EScout]

If you have a Magellan, like a Meridian, go to the "Position " Screen, and push Menu, then Projection, then either leave the "from" box to the current position, or select one of your waypoints. In the setup, set your distances to meters, and your reference to degrees and magnetic or true north.

 

If you have a Garmin, like a etrex Legend, choose a waypoint, they go to the menu at the top and choose projection. Set the bearing and distance. Again, make sure you have the units and north reference set.

 

The projected waypoint will have the lat and long. You can then do a go-to and find it.

[+fizzymagic]

Do NOT translate the coordinates to UTM to do projections! UTM's north is not the same as true north, so anything you do with it is likely not what was intended.

 

Instead, use your GPSr or my program GeoCalc to do the projection.

 

Oh, and the answer is

 

N 49 15.559, W 122 47.199

Edited January 8, 2004 by fizzymagic

[DrWongAndTheMoppets]

Thanks Guys, I gave GeoCalc a try and it works like a charm.

 

Now to decide..... Do I take my laptop out caching with me next time??

 

I think not.

[4x4van]

Geocalc works great sitting at home in front of the computer, but as EScout said, when you are out geocaching, just use the projection feature on your GPS unit.

[gilbertf]

I agree with Bobthearch. Compass is not that hard.

 

The first thing I learned was to use maps without compass. To find where I was and where to move. Then I learned how to use the compass alone, to be able to go anywhere AND go back as I wanted. With just a compass you might not where you are, but if you got a pencil and paper (or good memory) you will always go back to the start position. Best is using both map and compass of course

 

You can play the coin game with a compass. You take a coin like 1 $ or euro and put it on the ground. You get your compass, shot a random heading and count 100 steps or even more (counting steps is done by counting on left or right step but never both). Then you add 60 degrees right (or left) and walk again for 100 steps and add again 60 degrees and walk 100 steps. If you are precise with your compass, lay down and grab your coin

 

Walk is (excuse the crude map, was done hastily)

 

 

Used correctly and with two angle mesures from your position to easy, visible and non-moving points of reference, you can mark your position with precision, like in the niddle of a lake where you found a good spot for fishes

[Bobthearch]

The main trick is knowing how to pace accurately. In the triangle scenario above, your pace could be off by 50% or 200% and you would still come back to the dollar as long as you were consistently wrong each time.

 

Best Wishes,

Bob