An integral part of ecosystem-based planning is mapping and GIS. In the strictest sense, a GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e. data identified according to their locations.

GIS stands for Geographic Information Systems and is the generic name for a type of computer software which:

• Allows us to link maps of geographic (or spatial) information to computer data bases of attribute information. That is, the computer knows where things are located on a map, and it knows as many specific facts about each thing as we choose to tell it.

• Allows us to mix, match and compare maps to answer questions about how landscape features interact and relate.

• Allows a skilled user to answer complex questions about land and resources which were previously unanswerable due to real world funding and manpower limitations.

• Allows a skilled user to make elegant and attractive maps, which may or may not contain reliable and accurate information.

GIS is a fantastic tool for landscape planning and analysis, but it is more ideally suited to deep pocketed multinational corporations than it is to financially limited grassroots organizations. And while GIS makes gorgeous maps which can impress an audience, the maps may contain information which is unreliable or even wrong. Above all, GIS reflects the views, choices and assumptions of the users.

But the power of GIS is its ability to answer important questions about landscape ecology and resource use patterns, but only after paying the up front costs of acquiring and organizing a lot of data. The investment in developing an accurate, practical GIS database yields flexibility and depth of ecological and economic interpretations that were simply not previously possible. GIS enhanced ecosystem-based planning is particularly important where divergent interests and values need to be considered. In such situations, ecosystem-based planning defines the ecosystem composition, structures, and functions that are required to maintain short and long-term ecosystem functioning at all scales -- ecosystem health. Such an analysis serves as a foundation on which to base human use decisions and compromises.