The Survey of the Coast, in 1807, was the early beginning of the National Spatial Reference System (NSRS). However, active development of this national geodetic network took place in the first half of the 20th century. It was then that the U.S. Coast and Geodetic Survey, now named the National Geodetic Survey, invested an enormous amount of time and resources to develop a national network comprised of over 700,000 points.
This major effort has served the nation for nearly 100 years by providing a common base for latitude, longitude, height, scale, and orientation. It is unfortunate that today, as local demands on the network are increasing, the federal effort has slowed, especially with regard to maintenance and local densification. At the same time, the development of GPS technology has made geodetic control relatively easy, accurate, and affordable to produce at the local level.
Many older network stations are not suitable for use with newer positioning technology due to station deterioration or destruction, inaccessibility, or the obstruction of satellite signals. Thus, new control stations are needed in locations that will serve current and future positioning. It is this need that is driving the local densification activities currently taking place in over half of Wisconsin's county governments and many municipalities.
Today's geodetic network must be designed to accommodate a dramatic expansion of non-traditional applications, such as law enforcement, natural resource management, health and human services, and even hiking and boating. Efforts to meet this recent pressure have resulted in the development of several new standards for densifying and using Wisconsin's High Accuracy Reference Network (HARN).
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