Nonogram Mystery Cache

The cache is not at the published co-ordinates, but that is the best place to park your car. To find the co-ordinates for the cache, you will have to solve the puzzle. Don't forget to check your co-ordinates with the geochecker below, before you take the strenuous walk up the hill!

Bukit Kiara has many rough trails, but this cache is beside one of the sealed, easier roads. If you have walked on a footpath before, the terrain shouldn't put you too much out of your comfort zone, though the hill is steep in places! You might like to bring company, especially if you visit during a quiet time of the week. While the walking tracks on Bukit Kiara are busy on the weekends, early morning and afternoons, at other times they can be surprisingly quiet. Please exercise stealth, as GZ is visible from the path and the cache has gone missing before. And please use the clue to find the cache- the difficulty is meant to be in the puzzle, not searching amongst a forest!

Nonograms are picture logic puzzles in which cells in a grid have to be coloured or left blank according to numbers given at the side of the grid to reveal a hidden picture. In this puzzle type, the numbers indicate the sets of filled-in squares there are in any given row or column.

For example, a clue of "4 8 3" would mean that in that line, there are sets of four, eight, and three filled squares, in that order, with at least one blank square between successive groups.
(Ref: http://en.wikipedia.org/wiki/Nonogram)
 

Please note that the puzzle can be solved completely by logic. There is no need to make guesses, or even trial and error. But sometimes, there might only be a single logical step for you to take, and you might have to look long and hard! This puzzle will require some patience and mental application. The grid is 21 x 21 squares. To get started, look for sets of numbers that will completely fill a line with only the mandatory spaces. We have already coloured in a few boxes to help you out, too. These boxes form part of the completed puzzle, and thus are part of the provided number sequences, but even though they appear as single squares at the moment, they might eventually be part of a longer horizontal or vertical grouping. Remember, there must be at least one space between each set of numbers!

On successful completion, a second step is needed for the cache location to be revealed to you.

If you are using paper and pen/pencil, your working needs to be very neat for this second step to work. A better option is to use a Graphic program to fill in the squares, or a spreadsheet with the right sized squares.