A remarkably detailed map of what is today the state of Washington and the coastline of British Columbia was made only six years after Vancouver ’ s voyage . It includes closeups of Discovery Bay , Gray ’ s Harbor , and the mouth of the Columbia River . It even offers a hint of what is today Seattle , much of which was still unexplored . Vashon Island is immediately recognizable , but Lake Washington and Lake Sammamish are absent . The map ends at the slopes of the Cascades . That would have to wait to be charted by explorers from the East .
Although both Meriwether Lewis and William Clark had surveying experience , Clark was the cartographer of their expedition . Lewis was the navigator , trained to determine latitude by President Jefferson himself . For longitude , they needed a state-of-the-art chronometer , which cost 10 percent of their total supplies budget . The tedious process of charting every movement the team made slowed them down , but it was essential that all their maps be accurate .
Clark also copied maps drawn by traders and Natives , who often had serviceable maps of their own . In his journal of Oct . 18 , 1805 , Clark wrote :
“ The Great Chief and one of the Chimnâ pum nation drew me a Sketch of the Columbia [ River ] above and the tribes of his nation , living on the bank , and its waters , and the Tâpe têtt river which falls in 18 miles above on the westerly side .”
Drawn with a piece of coal on a buffalo robe , it depicts the Upper Columbia and Yakima rivers . Lewis and Clark did not explore that area , but it appears on the famous engraved map copied from Clark ’ s original , which bears the legend , “ A Map
50 ART CHOWDER MAGAZINE