I thought about the tent and chose the tarp because I assumed that the tarp would be the size of the one I have, which is 11.5 feet by 15.75 feet. It seemed to me that much material could be cut and fashioned into a variety of useful things. Also, the large size would collect a lot of rain water.

Most tarps have a silver side and blue side, which might also help in setting up some sort of signal.

It seems to me to be more flexible to meet different needs than a tent. But no doubt the tent would be more comfortable and effective shelter.