Some of the important uses for this information are to develop Federal funding justification, the state certified mileage report, local roads needs analyses and funding studies, map generation, required Federal reporting (Highway Performance Monitoring System), truck weight impact, and emergency response. These uses and the supporting data items need to be reviewed to determine if they are sufficiently important to justify the effort required to correct them in the Non-State Trunk Road Inventory file (NSTRI). The level of effort and process required to correct the data also needs to be identified and accurately assessed.
The current NSTRI system interfaces with the Highway Performance Monitoring System (HPMS), Railroad Crossing Inventory and the HR14 system (mainframe programs) which is used for state and federal mileage reporting requirements. Programs currently exist on the mainframe computer, which supports the above interfaces.
There is a need to bring the new GPS road track data and the mainframe NSTRI database together into one consolidated Non-State Trunk database. All data items need to be evaluated to determine if they need to be collected or remain in the database. Maintenance of the database is required to keep the data current. Any changes to the non-state trunk system such as realignments, abandonment, or new developments need to be reflected in the database.
SDDOT needs to determine which data items need to remain in the consolidated Non-State Trunk database and the most cost effective approach to correct the most critical Non-State Trunk data items. From this analysis, a more informed decision can be made regarding the value, support, and cost for updating the data for all the counties and cities.
Findings: GIS/Trans Ltd. provided consultant services to integrate the existing NSTRI database with updated information from a recently completed GPS inventory. The first step was to review the current environment of the NSTRI and the data items contained in it, as well as the data items contained in the GPS inventory. Recommendations were made regarding the suitability of retaining certain data items and all data items were ranked in order of importance.
Since there was no common key field in the databases, they could not be joined using standard database techniques. It was determined that using a Geographic Information System (GIS) to join the databases based on the location of the attribute sections was the most appropriate method to use. The GPS Inventory collected the road centerlines (basemap) with accurate road lengths (measures), and certain road characteristics as attributes. The GPS attributes could be placed directly on the basemap since their measures matched those of the basemap. The NSTRI method of locating attribute sections however, had to be converted into the same measurement system as the GPS. A Linear Referencing System (LRS) was created for the NSTRI which allowed the researchers to place the NSTRI data on the same basemap as the GPS data. Finally, the two databases could be joined by matching the route identifiers, and the measures for each attribute record.
Upon determining that the databases could in-fact be joined, procedures for maintaining and updating the combined database were recommended. Resources required to maintain the database were also recommended.