Data structure and concepts

The data contained within the GSD files comes primarily from two sources, premium street network data, such as the TIGER Census files, and the USPS ZIP + 4 files. GeoStan merges these files to create a complete and timely database that you can use to perform address standardization and geocoding.

Note: The following discussion specifically mentions TIGER data; however, the same information holds true for each of the premium geographic data vendors with which Precisely partners.

The data within the GSD files is organized into the following objects:

  • Street Objects

Street Objects are the highest level and contain information about the street as a whole, such as the predirectional, name, type, and postdirectional. Each Street Object can contain one or more Segment Objects.

  • Segment Objects

A Segment Object relates to only one Street Object. Segment Objects contain the latitude and longitude of the segment corners, shape points (to help define a street that is not a straight line), the left and right Census Block codes, and the maximum and minimum ranges for that segment. GeoStan derives the data for a Segment Object from the TIGER files. Each Segment Object can contain zero or more Range Objects.

  • Range Objects

A Range Object relates to only one Segment Object, and therefore only one Street Object. A Range Object contains low and high house ranges (including alphanumeric ranges), low and high unit ranges, the unit type (such as an apt. or ste.), ZIP Code, ZIP + 4 low and ZIP + 4 high, carrier route, and other USPS data. GeoStan obtains the data for a Range Object from the USPS files.

If an address does not have any Range Objects, the USPS does not have data for the address. Precisely data places street segments without ranges in the Ustw.gsd and Uste.gsd files.

There can be overlap within Range Objects. For example, one Range Object may contain house numbers between 100 to 198, while another Range Object may contain house numbers between 150 and 198. This frequently happens with high-rise Range Objects.

Because records may exist in one source that are not present in the other, there are occasions in which GeoStan may present only TIGER or USPS information. If Precisely was unable to match any TIGER records to a USPS record, a Segment Object may not contain any of the location and Census information. In this case, address geocode and Census Block information is not available. Conversely, there are records within TIGER that Precisely cannot match to any USPS records. In this case, no Range Objects may exist for that segment, and therefore GeoStan cannot standardize the address and cannot return the information available in the Range Object. This type of match does not produce a mailable address.