Hands On The exercise data is based on data from actual jurisdictions and represents field conditions but has been modified to protect sensitive information. Task 1: Understanding Addressing Data A typical PSAP will use several address datasets to place an incident on a map. A geocoding sequence starts with the most reliable, accurate, and current dataset available to identify a single point location on a map. To increase the success rate of the geocoding process, the service will standardize incoming addresses to match the reference data schema. Place-name alias tables also increase geocoding reliability. 1. Open the attribute table for GC1 Parcel Centroids and inspect its fields. Study the SITE_FULL field and sort it. Notice that each address includes one standardized string, possibly including an address numeric; a direction prefix, a street name, a street type, and a direction suffix. These address points provide a certain address match against standardized input data with a high degree of reliability. 2. Open the attribute table for GC2 City Streets and inspect its fields. This dataset, developed and maintained by the Lakewood Public Works Department, is current and complete. This polyline dataset separates addressing into left and right and to and from numerics, and includes separate fields for name direction and type. GC2 City Streets is the second geocoding data source. It supports a U.S. Streets Lowww.esri.com Create a Single Field Address Locator that references the GC1_Parcel shapefile. Continued on page 48 ArcUser Spring 2010 47