Maps have been used for
thousands of years, but it is only within the last few decades
that the technology has existed to combine maps with computer
graphics and databases to create geographic information
systems or GIS. The themes in the above graphic are only a
small example of the wide array of information that can view
or analyze with a GIS.
GIS is used to display and analyze
spatial data which are tied to databases. This connection is
what gives GIS its power: maps can be drawn from the database
and data can be referenced from the maps. When a database is
updated, the associated map can be updated as well. GIS
databases include a wide variety of information including:
geographic, social, political, environmental, and demographic.
GIS uses layers, called "themes," to
overlay different types of information, much as some static
maps use mylar overlays to add tiers of information to a
geographic background. Each theme represents a category of
information, such as roads or forest cover. As with the old
mylar maps, the layers which are underneath remain visible
while additional themes are placed above.
is estimated that approximately 80% of all information has a
"spatial" or geographic component. In other words, most
information is tied to a place. So when making decisions about
siting new facilities, creating hiking trails, protecting
wetlands, directing emergency response vehicles, designating
historic neighborhoods or redrawing legislative districts,
geography plays a significant role.
This is where GIS comes in.
Geographic Information Systems (GIS) technology is a
computer-based data collection, storage, and analysis tool
that combines previously unrelated information into easily
understood maps. But GIS is much more than maps. A GIS can
perform complicated analytical functions and then present the
results visually as maps, tables or graphs, allowing
decision-makers to virtually see the issues before them and
then select the best course of action.
Add the Internet, and GIS offers a
consistent and cost-effective means for the sharing and
analysis of geographic data among government agencies, private
industry, non-profit organizations, and the general public.
New Jersey State