Basically Botswana, although some misguided souls have said South Africa. Most of these parallel mark areas are to the south and west of the Okavango Delta. Some may reach into eastern Namibia. Since I have traversed areas several miles wide, crossing several channels at 50 or 100 feet, I would say that there is every little elevation in the mile between the channels. I suspect people lived along the channels, as some do even today, and used the mile between them for hunting and foraging. Some of the channels also hold water for part of the year and can probably be used for fishing.
Here’s one, but resolution is only 24 meters.............