I commence a Map of the Countrey on the Missouries & its waters &c. &c-
Clark was adept at using surveying and map making tools. He was a natural cartographer. He was also a good listener, and incorporated knowledge into his maps shared by friends including: Sheheke-shote, John Colter, and George Drouillard. Eventually Clark created a map, published in 1814, useful through later decades.
Another option to find your way with no map is to ask for help. Numerous American Indian guides helped Lewis and Clark find their way across the continent. Toby, Tetoharskry, Twisted Hair, and many more unnamed people ensured the success of the Corps of Discovery. When recrossing the Bitterroot Mountains west to east, Lewis was so desperate for American Indian aid he wrote:
June 18, 1806
We dispatched Drewyer and Shannon to the Chopunnish Indians in the plains beyond the Kooskooske in order to hasten the arrival of the indians who had promised to accompany us or to procure a gude at all events and rejoin us as soon as possible. we sent by them a rifle which we offered as a reward to any of them who would engage to conduct us to traveller's rest; we also dirrected them if they found difficulty in induciny any of them to accompany us to offer the reward of two other guns to be given them immediately and ten horses at the falls of Missouri.
That Lewis was willing to trade not only horses but firearms speaks volumes to how much he valued and needed American Indian guides. Then again, when lost, one of the best options is to ask for help.
The maps that William Clark and other cartographers made eventually led to the user friendly navigation systems that we use today. Despite the usefulness of GPS, electronic devices can fail for many reasons. If that happens, there are two good, if dated, alternatives. We can look at a map, and we can ask for directions.
Source: U.S. Department of the Interior, National Park Service