Using GIS - A Quick Example
© Gnomon, Inc. Carson City, Nevada
- Data source: Hepatitis A incidence registry, Clark County, 1994-1998 (n=1178).
- Data processing: geocoded (address matched) using TIGER line data (ca. 1990) and ETAK on-line processing. Approximately 70% of cases matched with TIGER data and some data editing. Of the remaining 30% of cases that would not match to TIGER, 80% matched to ETAK data. Final n of geocoded cases = 1110. Some of the excluded cases had addresses that could not be coded at all (e.g., “Lives In Truck”).
- Address matched records were overlaid on census tracts in a spatial intersection to encode census tract (FIPS tract value).
- Incidence was summed for each tract and joined to the tract geographic data set. Some simple measures were calculated including incidence per 1000 cases and proportion of 1997 population less than 5 years of age.