BOSTON — WHEN it comes to protecting the environment, it helps to have a very clear map, showing everything from possible pollution sources to water-monitoring stations to nearby schools and residences. But such maps, combining all such data anywhere in a state, usually aren't right at a regulator's fingertips.
In New Jersey, however, they are, thanks to the state's extensive use of Geographic Information System (GIS) technology. This system allows the layering of many kinds of information related to regions or counties and the instant graphical portrayal of that data on computer-drawn maps.
Applications are virtually limitless. Pat Cummens, chief of New Jersey's Bureau of Geographic Information and Analysis, describes how GIS capability can help state officials draft a law to protect a particular water supply. The computer can compile all relevant factors in the vicinity of the water - slope of the land, depth of the water table, land-use policies, nearby areas like wetlands that are regulated by the Department of Environmental Protection and Energy.
``You can analyze the impact of a bill before it becomes a law, to see if it's really necessary,'' Ms. Cummens says.
Or there's the ability to respond effectively to an environmental emergency. If an oil spill occurs - as happened in 1990 on New Jersey's Arthur Kill waterway - the GIS databank includes information on where oil booms and other gear are stored and on which areas, such as clam beds and bird-nesting sites, are most sensitive.
Henry Garie, assistant director of the Office of Information Resources Management, hits a few keys and calls up a map that simulates a spill. A line of ``funky hexagons,'' he explains, shows where the oil would travel over time. Superimposed on the map are charts showing the spill's impact on water birds at a given time of year.
``We map proactively, before any spill, so we're geared up to respond,'' Mr. Garie says. After the Arthur Kill oil spill, it took almost a year to complete a damage analysis. Now, using the GIS technology, ``you could have an immediate preliminary analysis,'' he says.
Another application could be the assessment of legal claims against the state. Cummens mentions a case from the Passaic River basin in northern New Jersey, where landowners have sued the state for allowing development in flood-prone areas. She produces a map on which red dots indicate the plaintiffs' housing and color gradations show the 10-year and 50-year flood plains. Lawyers will be able to use such maps as they deal with the claims, Cummens says.
The value of the system, like most databanks, depends on constantly updated information. The basic mapping data is provided by digital aerial photography of the state, which was done in 1991. The accompanying layers of data flow in from environmental-monitoring activities, local governmental units, and even private contractors who work with the state.
Cummens's bureau closely checks incoming information. ``We don't want garbage data going in,'' she says, since that would make the system unreliable. They've been compiling information since 1987, and Cummens sees no end in sight.
Cummens and Garie presented their use of GIS at the state technology displays set up in conjunction with the recent National Governors Association in Boston. A few other state applications include:
* Indiana's use of GIS to plan economic development using computer maps that show the transportation needs of future industrial sites.
* Puerto Rico's development of a GIS that allows mapping of the whole island, including soil, water, and land-use information.
* Wisconsin's use of GIS to coordinate state and local decisionmaking concerning transportation and other policy areas.