AccuGeocoder: Not All ZIP+4's have Census Information
The Census Tract and Census Block numbers are only added if the +4 for the Address Matches EXACTLY with the +4 in the Maponics Data.
We update the +4 code in the Maponics Data to coincide with the AMSDATA monthly, but the actual Maponics Data (Census data) is updated one time every two years.
The next Census update is 2010
If we added a Census Tract and Census Block number for NOT Exact Matches, both would be inaccurate.
The Lat/Long are added for NOT Exact +4 Matches because we can use the Sector or Segment to find the closest match to the +4 in the address database to the Maponics Data.
So the Lat/Long is still within the same Sector for example.
Those types of matches, NOT Exact matches will not give you a Tract or Block
The Lat/Long is added based on the Centroid of the 5-Digit ZIP Code if the Maponics Data does not have a Lat/Long for the +2
The USPS Database provided by the USPS is a Delivery Point Match.
We take that +4 code, which is an Exact Match to the Delivery Point (house/suite number) and attempt to locate that +4 code in the Maponics Data, which is compiled by Maponics, a 3rd Party, not the USPS.
Maponics uses the +4 assigned by the USPS at the time they establish the Lat/Long Tract/Block information and Maponics attempts to get as much Census data as it can.
The AccuGeocoder adds the Census Tract and Block number to records where the +4 is not an exact match to the Maponics Data.
There is also a field named CENSUS_RS (Census Match Result) that identifies at what level the match occurred.
| 04 = Exact ZIP+4 Match, i.e., 93422-2512 03 = ZIP+3 Match, i.e., 93422-251 02 = ZIP+2 Match, i.e., 93422-25 01 = ZIP+1 Match, i.e., 93422-2 00 = ZIP Code Match, i.e., 93422 |
