To solve the puzzle, you must fill in the empty circles with the numbers 1 to 7, following three simple rules:
- Each row must contain different numbers.
- Each column must contain different numbers.
- Each stream (circles connected by a line) must contain different numbers.
Once you've filled in the missing circles according to the rules, make note of the numbers in the circles designated A through F. Use those numbers for the coordinates, according to:
N 47 41.ABA W 122 19.DEF.