A projected waypoint is where a second waypoint is a given bearing and distance from a given waypoint.
Many GPS receivers can perform this calculation but for those that don't, here is how to manually calculate the second location.
And by manually we mean with a trigonometic table book or slide rule, pen and paper.
i.e. Your Laptop, PDA, mobile phone and calculator have flat batteries leaving only the GPSr working.
This will only work for a few kilometers but should be fine for caching. I'm assuming you are in Australia.
A book with sines and cosines or a slide rule and the ability to perform simple maths without a calculator!
You have printed this out and put it in your Geocaching folder!
Sorig is the first southing in the form dd mm.mmm
Eorig is the first easting in the form dd mm.mmm
D is the distance from location one to the second location in metres.
B is the bearing from location two to the second location in degrees.
S is the southing in the form DD.DDDDD, calculated from Sorig
First lets calculate the distance in the southing and easting to the second location in metres.
deltaS = -D * cos(B)
deltaE = D * sin(B)
Now we need to convert this distance in metres to minutes of latitude and longitude.
deltaSmin = deltaS / 1853
deltaEmin = deltaE / (1853 *cos(S))
These are the variations to the minutes in the form mm.mmm
This is based on 1 minute of latitude 1nm. (1nm = 1853m)
The deltaEmin takes into account as you move towards the poles 1 minute of longitude gets smaller.
Snew = Sorig + deltaSmin
Enew = Eorig + deltaEmin
Sorig S34 46.533
Eorig E138 36.090
B 25 degrees
therefore S is 34.77555, cos(S) = 0.821
deltaS = -800 * cos(25)
= -800 * 0.9063
deltaE = 800 * sin(25)
= 800 * 0.4226
deltaSmin = -725 / 1853
deltaEmin = 338 / (1853 * 0.821)
Snew = S34 46.533 - 0.391
= S34 46.142
Enew = E138 36.090 + 0.222
= E138 36.312