Ground Cloth
A ground cloth is usually a large square piece of Oxford cloth or PE fabric. Its primary functions are moisture-proofing, water resistance, and expanding the usable area under a tent. It generally doesn’t have an aluminum foil layer. Of course, neither Oxford cloth nor PE is lightweight, so a large piece like this can be quite heavy. If you’re planning a trip for just one or two people and want to keep things light, it’s better to choose a lighter ground mat.
In outdoor activities, the ground cloth is usually placed at the bottom layer, the ground mat in the middle, and the sleeping pad (inside the tent) on the top. Of course, for very casual camping, bringing just a ground mat or a sleeping pad is usually enough.