Thomas Jefferson had been interested in exploring the west well before the 1803 Louisiana Purchase for France. During the 1780's and 1790's, he championed a few failed attempts at such an exploration. Believing the United States needed to expand west to help ensure its survival and prosperity, he jumped at the chance to buy Louisiana from France's Napoleon Bonaparte.
President Jefferson wanted the Louisiana territory explored because he wanted friendly contract with the native Americans that wanted to trade goods or to find the northwest passage or to find out what the United States had bought
Von Thunen is famous from the 19th Century. He made a model that showed how market processes how to use the land in various locations. I hope this helps!
