MapInfo®, Streetworks® and MapMarker® are used to create the street address database. Streetworks® contains a database of street segments based on street centre lines, intersections and street numbers at the end of each segment. An in-house linear interpolation program converts the segment data to a list of addresses within each study area. The assumptions made by this program are:

• The Streetworks® database is an accurate listing of segment data
• Addresses are equally spaced along the segment
• Numbering is consistent with addresses at each end of the segment
  • Even at both ends - interpolates only even addresses
  • Odd at both ends - interpolates only odd addresses
  • Mixed even and odd - addresses consecutively numbered
• Addresses are only whole numbers; 15A, for example, does not exist
• Houses are offset 20m from the road centre line

As we do not know whether the parcels of land included in the list are occupied by a house, a commercial/industrial property or are vacant land, they are best referred to as street addresses.

Each street address is spatially located using MapMarker®. Comments are added to the database to identify potential problems such as addresses that are represented by street centroids only and those that could not be geo-coded at all. Generally, over 95% of addresses in each study are successfully geo-coded.