We are given a jpg file and coordinates: 7º 2' 34.46" W 54º 41' 54.28" N
This problem was really just checking if you could figure out which cipher it was. I did spend a bit going through a bunch of image stegonography tricks before realizing the image itself supposed to be decoded. A search for "cipher with horizontal and vertical lines" had the Ogham cipher as the first result.
We could either use the dCode, or this Ogham alphabet key. In the image given, the top is the start, but we will need to rotate it so that the left is the start. Once that is done, it's a simple matter of just looking at each group of lines and seeing what they represent. The flag, in all caps: