GIS is short for geographic information system. From Wikipedia: “In a general sense, the term describes any information system that integrates, stores, edits, analyzes, shares, and displays geographic information. GIS applications are tools that allow users to create interactive queries (user-created searches), analyze spatial information, edit data in maps, and present the results of all these operations. Geographic information science is the science underlying geographic concepts, applications, and systems.”
Douglas County recently upgraded their GIS offering in a big way and have made it easy to find information about real estate and the layer with leaf-off aerials from 2016 also will give you a very good feel for water depth and the bottom of the lake. Check it out. It is a wonderful tool. Below is an example in a screenshot of a portion of an area of Three Havens.