Pike's map of Texas and the Southwest is the first map of the Southwest to be based on firsthand exploration and is widely regarded as one of the milestones in the mapping of the American West.
Based in part on the maps of Alexander von Humboldt, which were available to Pike in Washington, Wheat notes that the map provides a critical first hand look at Texas and the West at the opening of the 19th Century and offers a remarkable picture of an important stretch of country that had hitherto been known only through the vaguest of rumors.
In 1807 Pike led one of the earliest expeditions to reconnoiter the newly purchased territory of Louisiana.... While similar to Humbolt's map, it provides a significant improvement in rendering the interior of Texas. With the exception of the lower courses of the Sabine and Neches, which are distorted to the East, the Rivers are shown accurately. The Brazos is, for the first time in a printed map, shown in almost its proper length and shape.
Lake Timpanogos still appears, as do several of mythical rivers in Utah. Includes fascinating early notes on the exploration of the west.