Sex Offender Proximity Analysis

The purpose of this analysis was to determine the high-risk areas within Riverside County where registered sex offenders could threaten children. To obtain this information, four different data sets were combined to locate these areas. The data sets included addresses of registered sex offenders, census block information, and locations of schools and parks.

Data on the addresses of known sex offenders was buffered at one-half mile intervals up to five miles. Those intervals were reclassified into zones 1 through 10. Ten represents the closest zone to the location of the sex offender and one the farthest away.

The census block data set was reselected for the median age of 18 and under. Of the census blocks selected, the population under the age of 18 was 50 percent. This data was also buffered at one-half mile intervals up to five miles. The zones were reclassified in the same manner as the sex offender addresses. The schools and parks data sets were similarly buffered and reclassified.

When the data was reclassified, the raster calculator in ArcGIS Spatial Analyst combined the information and weighted it as follows: sex offenders, 60 percent; schools, 30 percent; parks, 5 percent; and census block, 5 percent. The result of this calculation showed the most probable spot in Riverside County where a possible sex offense might occur against a minor.