A funny side note... When I arrived at the park early in the early morning, there were a few cars ahead of me. I didn't want to compete with other photographers so I found a place to park a little off the beaten track. When I got on the sand, I took a photograph of my long shadow with my iPhone and then I put it away and got on with the business of taking photographs with my camera. I wandered for about an hour, not paying attention to where I was going. Before long, I had gotten totally disoriented and couldn't remember where my car was. All the dunes looked the same so there were no landmarks. I suppose the position of the sun should have been a consideration but it wasn't in the heat of the moment. I walked in the direction I thought I had come from but after about 40 minutes, I was beginning to worry. There was no sign or sound of the road where I had parked. Keep in mind that there were dunes for as far as the eye could see. I might as well have been in the middle of the Sahara.
Luckily, I had a cell signal and was able to map where I was using GPS. It showed I was relatively near the road. I finally found it but the road itself was equally generic. I had come out at a completely different place from where I had entered. I began to walk in the direction I thought best but, let me tell you, my sense of direction is never right. More time elapsed and more distance was covered but still no sign of my car. Then it dawned on me, I had taken that photo with my phone near my car. I extracted the geotag info from it and realized I was walking the wrong way. I finally got turned around and found my beloved vehicle!
Dumb things I did: i left my water in the car and didn't pay attention to my path.
Had I not had cell service, I'm not sure how long it would have taken me to figure out where I was. We've all heard horror stories of these kinds of events. So beware if you go to a place where the possibility exists that you might get lost. At the very least, bring lots of water with you.