But aerial images should not be the sole factor for hiking trails. If its a road, or rail trail or paved surface that is easily visible, that I could understand. The trails here don't look like they are maintained, and particularly in the southern part of the park there are areas that I think might have changed slightly. 

I am confident with the reliability of my GPS data. I often Avenza with maps that have been professionally made, and in many cases my tracks line up perfectly. 