Software Can Map Out the Future
When a special three-judge panel was appointed by the California Supreme Court to redraw political district boundaries for the state, the panel used Atlas GIS mapping software on personal computers to do the job.
And when newspapers such as The Los Angeles Times recently published maps of those new boundaries, the same Atlas software was the starting point.
Data mapping on personal computers has come of age, and the 1990 census is providing unprecedented access to a wealth of data to be mapped.
Atlas GIS, $2,495, for IBM compatible computers only, is the top of the line mapping package from Strategic Mapping Inc. of San Jose (408) 985-7400. Strategic Mapping also publishes Atlas Pro, $795, for DOS and Macintosh and Atlas MapMaker for Windows and Macintosh, $395. Atlas GIS for Windows and Macintosh is expected later this year.
Data mapping involves two elements:
* The geographic boundaries plus associated features, such as roads, railroads and rivers.
* Data related to the geography, such as population or sales by ZIP code.
The difference among the various Atlas products is the degree of data manipulation that can be performed. The high-end GIS package takes its name from geographic information system, and it allows complete analysis of data by geographic location. The MapMaker products are more limited, lacking a real underlying database, relying instead on a simple spreadsheet to match data with geography.
The high-end database capability was crucial for the court’s reapportionment panel, which faced a formidable task. To meet legal requirements, they had to draw political districts equalized in population for Congress, the state Assembly and state Senate. And they also had to create districts that would unite ethnic and racial minorities to give them maximum opportunities to elect their own representatives.
From the census, the population, racial and ethnic composition of each census tract were known, along with the precise boundaries of each tract, measured in latitude and longitude accurate to six decimal places. Strategic mapping was able to provide data files for Atlas GIS containing both sets of information. It also provided boundaries for counties and cities.
The software could display all of this information on the computer screen in any degree of detail desired. Census tracts could be colored according to various levels of Latino population, for instance, to see where they were concentrated. Those tracts could then be selected on the screen, by pointing at them with a mouse, to group them into a political district.
The population of a district being created could be monitored. When it reached the desired size, work could begin on another district. At the same time, districts could be drawn to coincide with city and county boundaries. Then they could be fine-tuned by shifting tracts from one district to another.
The result was a set of boundaries largely contiguous with counties and cities, well-matched in population size and giving minorities maximum clout. Another result was that the boundaries existed as Atlas data, so that the only way to map them in any detail was to use either Atlas Pro or GIS software.
Virtually any kind of data that is related to a geographic location can be best displayed on a map. The Atlas programs can produce a wide variety of maps, which can include bar or pie charts, colors, shading and other methods of depicting data measurements.
But it may take something extra to get just the right look for publication. The political district maps printed by The Times, for instance, started in Atlas Pro on the Macintosh, then were moved into Aldus Freehand illustration software to get better control over styles and weights of lines and tones and to add explanatory text and tables.
However, you can do something with the just-released Atlas Pro on the Macintosh that can’t be done on a PC or in newspapers--play movies. Making use of Apple’s QuickTime video capability, a realtor could highlight a neighborhood on a map on the screen and then have Atlas Pro play a video of each home in the neighborhood that met the customer’s criteria for price and features.
Computer File welcomes comments but regrets that the author cannot respond individually to letters. Write to Richard O’Reilly, Computer File, Los Angeles Times, Times Mirror Square, Los Angeles, Calif. 90053.
