UP206A: Introduction to GIS
» Geocoding is the process of assigning a location, usually in the form of coordinate values (points), to an address by comparing the descriptive location elements in the address to those present in the reference material.
» Many reasons. ˃One is to be able to determine which boundary (e.g. school district, census block, voting district) a particular address is contained. ˃To visually see if data is clustered or dispersed ˃To summarize data by a larger geography ˃Display points based on certain parameters » To extract information from an address that the address does not immediately offer.
» Inconsistent » Incomplete » Not in the correct address format » Data not collected for research purposes
» Are the points being placed where they should be? » Depends upon accuracy of address and road network. » Score » Informal Checks ˃Compare against existing data, known points. ˃Check against Zip Code boundaries, quadrants ˃Last resort: Check against Google, Yahoo online geocoders!