A brown map is an exercice to focus on contours training.
To make it, you just hide all th symbols except the brown ones on the map and then plan a course.
To make it less difficult, you can plan a star course and leave the paths. Be careful with the instructions: the paths are only there to relocate if necessary, not to get as close as possible to the control by avoiding reading the contour lines 😉
To make it more difficult, you can get rid off the North lines
This exercise is “scary”. It is a good idea to propose different steps before going into a complete brown course: brown and path star course, brown star course, then small loops. Also let people having a spare map, in the pocket.