The GPS Connection
Source: Significant Digits
SDI's GPS Connection is offered in several different packages of varying price and plotting accuracy. The levels, starting from least accurate to most accurate are, plotting by 911 addresses, low performance GPS gathering, Trimble high performance GPS and Trimble high performance GPS with post processing. The cheapest and least accurate way to plot points is 911 address plotting. Microsoft MapPoint has a database of coordinates for 911 addresses. These are easy to obtain, but the downsides are that not all addresses have an associated GPS coordinate. They are not very accurate and represent a general location rather than a specific point.