At the posted coordinates you'll find a sign (or two) with a map on it.
Locate the sign with a number in the format of XXXX-YY
A = (XXXX/YY) - 10.
B = ((YY * 3) - 2) + 0.595.
Perform a projection of A meters at B degrees.
Once at GZ, locate the container and gain access to the log.
This cache was placed with the intention of being found for GAG31, which takes place on October 20th at 6pm.
Enjoy