THE WEDDING of one of man`s oldest tools–the map–with one of his newest –the computer–has produced a new breed of ”supermaps” that enable officials to better understand and govern complex cities like Chicago.
So potent is the marriage, say experts, that virtually every bureaucratic detail about a city–from the location of fire hydrants to the distribution of homes with delinquent water bills–can be displayed instantly on color screens or printed almost as fast on paper maps.
”We`re looking at a major revolution in the way cities keep track of themselves,” said Charles O`Connor, superintendent of maps in the Chicago Department of Public Works.
Much of the new technology was spawned by defense contractors in the late 1960s and early 1970s during the development of cruise missiles and other geography-based defense systems.
Cruise missiles use radar to ”read” the terrain between launch site and target. Radar images are constantly checked against a detailed topographic map stored in the missile`s mini-computer. Course adjustments are made so the radar sees what the computer expects.
By the mid-1970s, a half dozen high-technology firms were marketing ways to apply similar mapping technology to the most complicated real estate of all: the modern city.
Suddenly it was possible to electronically catalogue the exact location, condition, even ownership, of what had been an unknowable jungle of streets, sewers, utility lines, tax parcels and structures.
Theoretically, one person at a display terminal can call up data heretofore scattered about the local bureaucracy in file cabinets, tract books and microfilm libraries hidden away in dank city hall basements.
Chicago was one of the first big cities to computerize basic information about itself. The city bought an Intergraph-brand geographic information system (GIS) in 1978 and has painstakingly built an electronic base map of streets and waterways.
Other cities started later but moved faster. That`s partly because Chicago has not funded its program as well, and partly because turf-conscious city and county officials in Chicago have been slow to share their files with a central computer.
Even so, Chicago is electronically mapped down to the block level.
A city planner who wants to know the location, say, of street repairs financed by federal funds, can keystroke the question into his graphics CRT terminal and within seconds view a citywide display of such repairs. From there the operator can zoom down to a single block or grouping of blocks for a more detailed breakdown.
The next step for Chicago–a step several cities already have taken–will be to expand the system down to the parcel level. Operators will be able to focus on any real estate parcel in the city to see who owns the land, what structure is on it, plus any desired combination of administrative details ranging from zoning status to housing code violations.
”The sky is the limit,” said Dorothy Besal, director of research for the city`s Department of Planning. ”You could inventory trees if you wanted. The only limitation is imagination and your pocketbook.”
The city`s mapping system has already become ”a sophisticated management and analytical tool,” Besal said.
For instance, by feeding U.S. Census Bureau tape files into O`Connor`s base map, Besal`s section can instantly produce shade-maps showing relative concentrations of Italians, high-income households, unwed mothers or any other group the census counts.
”No more shading in census tracts with colored pencils,” Besal said.
Once the data are on the system, Besal said, decision makers can order up maps that graphically represent the geographic spread of problems or possibilities.
”Maps help people see things they might otherwise miss,” she said. They might show concentrations of children between the ages of 6 and 12 in need of a branch library, of older frame houses in need of more fire protection, of neighborhoods in need of another bus route or police beat.
To be sure, some ”Big Brother” questions arise.
Should a clerk in the county recorder`s office, for instance, be able to look up which of his neighbors are behind on water bill payments? Or for that matter, should anyone in government be helped to correlate, say, the racial makeup of neighborhoods with the incidence of venereal disease or crime?
Proponents of the new technology make two points. First, nearly all the data are ”public record” to begin with; the computer merely speeds look-up time and makes possible cross-tabulations. Second, most systems have authorization codes and lockout mechanisms to make sure only certain operators have access to certain types of data.
”I don`t think there`s a Big Brother aspect at all,” said David Webber, an Intergraph sales representative. ”In fact, we`re making it so easy to access public records that it`s the opposite situation . . . the average citizen can find out things only the experts used to know. It`s a great equalizer.”
Webber would get little arguement from any layman who has attempted to look up, say, the owner of a piece of real estate in Chicago. The seeker must first obtain a legal description of the property from maps kept by the Cook County clerk`s office; then find that parcel in tract books maintained by the county recorder`s office; then go to a microfilm library to view an actual photo of the title document. The three-office chore takes a half-hour, minimum.
Still, some think technology could make government recordkeeping uncomfortably efficient.
”The most common complaint we get,” said one electronic map expert,
”is from people who don`t like the idea of city hall tracking their property . . . maybe they built an addition to their house without a permit.” In fact, supermaps can be used to detect cases where the actual use of land is out of conformance with theoretical use. Aerial photographs of a city can be overlain on maps showing the boundaries of flood plains, nature areas or special zoning districts. Violations can be identified and the owners cited without a city inspector having to leave his office.
Before a city gets to that point, however, it must first create an accurate ”base map”–a map that pinpoints the precise longitude and latitude of its streets and borders. There are several ways of doing this.
If an accurate conventional paper map is available, its features can be entered into a computer by placing the map on something called a digitizing table. The table is a light board with a fine wire grid (.001 inch)
underneath.
The mapmaker traces the printed map with a hand-held electronic cursor, called a mouse, which translates the map`s lines into electronic impulses as latitude and longitude, or X and Y, coordinates.
If no reliable printed map is available, a city may want to undertake a theodolite survey. Chicago commissioned the National Geodetic Survey to perform such a survey 10 years ago, O`Connor said.
Triangulation stations were set up atop 100-foot-tall towers at 43 precisely known points around the city. Surveyors equipped with special electronic transits, called theodolites, roamed the city and, using the towers as reference points, recorded the exact location of streets.
Taped information from the theodolites was fed into a computer, called a central processing unit, which produced what O`Connor calls the city`s first truly accurate map.
Once its base map is complete, a city can stock its central computer with a wide variety of map overlays, each with its own internal boundaries. Chicago`s Intergraph system offers 63 separate overlays–far more than could ever be possible with a single paper map.
Popular overlay categories are census tracts, zoning districts, structure outlines, police beats, ZIP codes and ward and precinct bondaries–any of which can be superimposed on any other. It is possible, therefore, to produce a map showing which census tracts are in which ZIP codes, or nearly 4,000 other combinations.
Huge inventories of site-specific things also can be added. Chicago, for instance, is loading its VAX 11/751 32-bit central computer with the location of such things as fire hydrants, streetlights and traffic signals–each correlated with the closest street address.
There are problem areas, of course.
A big headache for Chicago and other older cities is the need to reform data provided by scores of tradition-bound city departments, each with its own ways of recording things.
Another hurdle is what to do about changes. That is, after each department`s data are loaded onto the electronic map, a way must be found to update the map every time a house is sold, a street widened or a hydrant painted.
And as might be expected, the technology involved does not come cheap. Chicago has spent well over $2 million on computer mapping since 1978.
Cities that have pushed ahead to the parcel-level–such as Milwaukee and Houston in this country and Edmonton in Canada–have found it can cost from $3 to $15 a parcel to load all the desired data into their system. Chicago, keep in mind, has 600,000 tax parcels.
On the other hand, cities are beginning to claim huge savings as computer mapping begins to replace more labor-intensive methods of recordkeeping, and begins to improve management itself.
New York City officials say they have saved $5 million to $8 million since installing their system four years ago. New efficiencies have a ripple effect across the entire city budget, the officials say. For instance, a citizen`s complaint about a broken streetlight can be instantly plotted and made part the next day`s job list for the closest city crew.
”It`s definitely the way things are headed,” concludes Chicago`s O`Connor. ”For the first time, we have a tool that can tell us exactly what`s out there.”
