GIS Applications in Agriculture, Volume Four: Conservation Planning, edited by Tom Mueller and Gretchen F. Sassenrath, is the fourth volume in the book series GIS Applications in Agriculture, which is designed to enhance the application and use of geographic information systems (GISs) in agriculture by providing detailed GIS applications that are useful to scientists, educators, students, consultants, and farmers. The first volume, GIS Applications in Agriculture, edited by Francis J. Pierce and David Clay, was published by CRC Press in 2007. The second volume, GIS Applications in Agriculture: Nutrient Management for Improved Energy Efficiency, edited by David Clay and John Shanahan, and the third volume, GIS Applications in Agriculture: Invasive Species, edited by Sharon Clay, were published by CRC Press in 2011. While the newest book in this series, the idea of a book on conservation planning using GIS was identified in 2007 when the book series began. Intuitively, conservation planning through GIS applications should appeal to all conservationists who clearly understand that a key to achieving soil and water conservation is rooted in an understanding of the spatial and temporal variation in both soil and water resources and natural and human-induced forces that affect the quality and quantity of those resources. <...>

What is cartography today? When I look back on the first and second editions of this book, it’s almost like seeing cartography as it progressed since 2009 and it now looks almost nothing like it did then. The expansion of what’s possible has been incredible. Massive technological change, accompanied by free, open, highly detailed, and reliable datasets, along with a surge of interest in the field from all corners, combined to make what was once impossible cartographically, possible.

About 2,200 years ago a scholarly librarian in charge of the prestigious collections of the museum at Alexandria conducted an elegant exercise in logic and experimentation. Using seemingly unrelated bits of information such as the observation of the penetration of sunlight into a well in the city of Syene, the speed of a camel caravan, and the shadow cast by an obelisk in Alexandria, Eratosthenes calculated a remarkably accurate estimate of the circumference of the earth (Wilford 1981).