The earth is a fragile planet with finite resources. These resources are shared by increasing numbers of people. The results of our habitation of the Earth has meant decreasing wildlife and plant species as humans encroach, modify and destroy their domains. To manage these changes, we need accurate and up-to-date information that will guide our actions and policies. Much of this information is required in geographical form; in other words, we need to answer some basic questions such as: What is it? Where is it? How big is it? How will it affect those around it? etc. The surveying profession has provided the tools such as geographic information systems (GIS) and satellite positioning, the skills, and information to answer these questions, and many, many more about the physical environment of our planet and how our actions affect it now and in the future.
Maps have traditionally been used to explore the Earth and to exploit its resources. GIS technology, as an expansion of cartographic science, has enhanced the efficiency and analytic power of traditional mapping. Now, as the scientific community recognizes the environmental consequences of human activity, GIS technology is becoming an essential tool in the effort to understand the process of global change. Various map and satellite information sources can be combined in modes that simulate the interactions of complex natural systems.
The condition of the Earth's surface, atmosphere, and subsurface can be examined by feeding satellite data into a GIS. GIS technology gives researchers the ability to examine the variations in Earth processes over days, months, and years. As an example, the changes in vegetation vigor through a growing season can be animated to determine when drought was most extensive in a particular region. The resulting graphic, known as a normalized vegetation index, represents a rough measure of plant health.