A Web Application Approach to Street Sign Inventory Development

Maintaining accurate and comprehensive spatial data on infrastructure at the municipal scale is a challenge that comes with serious challenges. Obtaining such data often requires such extensive resources and time that many municipalities may completely abstain from even considering this seemingly insurmountable task. Regardless of these substantial hurdles and the additional budgetary constraints imposed by difficult economic times, municipal infrastructure maintenance and repair is a necessary function of a municipal government. In the case of street signage, formally part of the umbrella known as traffic control devices (TCD), this municipal role has come to be required under federal regulations. To aid local governments with this critical function in a cost-effective manner, Georgia Tech researchers developed a web-based application in the fall of 2010 that utilizes Google Street View to remotely locate and catalogue street signs in an urban environment. This inventory tool, dubbed CityPoints, proves superior to field identification using a GPS unit because of an increased positional accuracy and decreased cost of both time and labor. The density of urban space requires a finer resolution than most GPS units can provide. On top of this inherent flaw, there is an increased risk of positional inaccuracy due to interference caused by the reflection of satellite signals against medium- and high-rise buildings, making an approach based on in-field GPS data collection wholly insufficient. CityPoints’ time and labor savings result from the convenience and accessibility of the Street View technology. Accessed through any Internet-connected consumer workstation, the web-based application eliminates the travel component associated with field work and enables data collectors to work independently in an office or other indoor environment. Users input data directly into a backend database associated with the web application, which again reduces labor over the conversion of handwritten data to a digital spreadsheet format that may be involved with field data collection. In spring 2011, a studio of Georgia Tech graduate city planning students assessed the real world applicability of CityPoints. Their assessment included the development of use instructions for municipal employees (Appendix 3), a comparison of both the rate of data production and the accuracy of data produced using a GPS unit versus CityPoints, statistical analysis of data collected with CityPoints to estimate the number of street signs in the City of Atlanta, and a couple of corollary reports on the use of CityPoints for other applications (Appendix 1). Conclusions of their work confirmed the efficiency of the web application method over GPS field data collection. Though field work maintains some advantages over remote data collection, such as the visibility of more recently added features and signage, CityPoints allows for drastically reduced time and labor costs, while still maintaining its edge on positional accuracy and precision. Having collected data with CityPoints, researchers refined and enhanced the information with GIS and developed models with which they came to statistically sound estimates of the number of street signs.