Creating Your Own Data ArcView_module_13 May 16, 9:00 AM

Outline What is Geocoding? Address Geocoding Requirements How it works

Geocoding establishing the relationship between page coordinates on a planar map and known real-world coordinates Geocoding lets you create spatial data from the attributes about the location. Descriptive Data Spatial Data (x,y)

Address Geocoding The process of identifying the coordinates of a location given its address Patients Addresses Patients Layer

Requirements for Address Geocoding Address Table Reference Theme : street data against which the addresses are matched (e.g. TIGER/Line Roads)

Reference Theme Street NameAddress RangeZip Direction Prefix, Street Name, Street Type, Direction Suffix FromAddressLeft, ToAddressRight, FromAddressRight, ToAddressRight ZipLeft, ZipRight

How it works 1. Make a reference theme matchable Specify the fields used to geocode 2. Compare addresses in the address table with the address attributes in the matchable reference theme Address within address range? Same/Similar Street name? Eg. 350 Old Geneva =~ Old Geneva Rd Geocoding Process

How it works ArcView applies standards and rules to make decisions about whether addresses match (e.g. standardizing address components, spelling sensitivity, minimum match score, minimum score to be considered a candidate) 3. If a match is found, geographic coordinates are derived from the matched feature and assigned to the address Geocoding Process

How it works Address Table A Matched feature in the Reference Theme Geocoding Process

Figuring out unmatched cases There are many reasons why some records are not matched the address information given may be wrong (e.g., confusing street type (Niagara st? Niagara rd?), wrong zip code) The attributes in the reference theme is not complete the address uses some alias (e.g. hospital name, building name) the standardization may be wrong