I like what you've done with the graying out of the passages, coupled with a good dm description as the adventurers go through them, sharp pc's will pick up that the passages are less traveled. However, the symbols are now so faint that they are hard to read. If thats what you want great, but the effect would look much better on a "worn" parchment/paper style map found by the pcs. Also, while I think the satellite image you picked for the outside looks spectacular, it really clashes with and does not go well with the rest of the map. Maps (at least to me) look best when they have one unified style and are not a pastiche. Keep the outlines of the canyon, but trace over the river and major features with your program and then eliminate the image. You'll still have the outlines of the canyons features, but will have a unified overall look to the map.