Calif. counties map offenders' homes

San Diego County's Web site marks the location'to within a half-block'of sex offenders' homes with blue circles. Green markers indicate schools.

Los Angeles County last month approved a plan to post on its Web site the locations of convicted sex offenders' homes to within a half-block.

The county took as its model a San Diego County site that officials called a pin map.

California law doesn't permit counties to post the street addresses of sex offenders on the Internet, said Tony Bell, communications director for county supervisor Mike Antonovich. But citizens can visit a sheriff's office to look up names, photos, addresses and rap sheets of local sex offenders on a CD-ROM, which the Los Angeles police department updates monthly, Bell said.

Visitors to the Los Angeles site can search areas by ZIP code, nearest intersection, school, library or park. The site places blue circles over the home locations of offenders convicted of a violent sex crime. Tan squares indicate high-risk offenders, which California law defines as those convicted of more than one violent crime, at least one of which was a sex crime.

The San Diego County site, launched July 1 at, was built by the San Diego Processing Corp., a nonprofit that serves as the city's IT agency.

The Los Angeles Board of Supervisors decided to use San Diego's system as a base and layer Los Angeles' geographic information system data over it, said Jonathan Ames, webmaster for the San Diego site. It would have cost Los Angeles twice as much to build a system from scratch, Ames said. Layering on top of San Diego's system also will cut deployment time by three-quarters, he said.

The San Diego site uses ArcInfo GIS software from ESRI of Redlands, Calif., and an Oracle8 database. The county system links through a secure portal to the San Diego police department for updates, Ames said.

About the Author

Trudy Walsh is a senior writer for GCN.

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