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“I am a big advocate of geospatial data,” says Anthony Goodnight, Huntington’s director of public works and engineering services. “When you can see pictures and query data on a map, it’s so much easier to get information.”
Located near Fort Wayne in northeastern Indiana, Huntington decided to map the locations and retroreflectivity scores of its traffic signs after FHWA issued its May 2012 final rules revision to the Manual on Uniform Traffic Control Devices (MUTCD). Under the ruling, state and local agencies have until mid-2014 to implement a plan for maintaining sign retroreflectivity at or above levels established in 2009.
Retroreflectivity is a value that quantifies the ability of a surface to reflect light back toward its source. In the case of road signage, this increases visibility to drivers at night when their vehicle headlights illuminate the signs. Most modern traffic signs (stop, yield, etc.) have special backing and legend materials that make them more reflective. However, these materials degrade over time as sunlight and weather take their toll on sign surfaces.
As will be true for cities and counties nationwide, Huntington will develop an upgrade and replacement strategy that is financially feasible and gives priority to worn-out signs. But before the signs can be replaced, they have to be evaluated and mapped.
To perform the sign inventory, the city contracted DLZ Corp., a Midwest engineering, architecture, planning and surveying consulting firm. For similar projects in other cities, DLZ deployed a custom mapping and GIS data collection solution it had developed using GPS-capable Apple iPad 2s and a mobile data collection app called GeoJot.
The maintenance of signs and other infrastructure in Huntington falls under Goodnight’s jurisdiction. For the last sign inventory in the late 1990s, field crews had taken to the city’s streets using measuring tapes to record the distances that traffic signs stood away from road centerlines or intersection corners. These location descriptions were entered into an Excel spreadsheet with no connection to the GIS, which is shared by the city and Huntington County. The department saw the MUTCD revisions as an opportunity to bring the sign inventory into the digital environment of the GIS.
GIS data collection is a service DLZ often performs for its clients, usually involving the mapping of feature locations along with the recording of specific attribute information. Having experienced frustration with inflexible data entry capabilities and poor camera quality on other GPS-based field mapping devices, the firm gave the iPad a serious look as a GIS data collection tool shortly after it was released.
The large touchscreen appealed to field crews, and the introduction of built-in GPS and digital compass in the 3G models of iPad 2 tablets made them legitimate mapping tools. DLZ also liked the quality of photos captured with the iPad. “The photos from our previous data collector were comparative to a flip phone–pretty rough–not the best for expanding and enlarging,” explains John Nelson, DLZ project manager.
A quick Internet search found the GeoJot mobile field app, developed by GeoSpatial Experts of Thornton, Colo., to turn the iPad 2 into a mobile GIS data collection system. The Colorado firm created the GeoJot app specifically for mapping professionals as a companion to its longstanding photo mapping software, GPS-Photo Link. Both the mobile app and mapping software have since been incorporated into the GeoJot+ mobile data collection system.
GeoJot was attractive to DLZ for its ability to synchronize photos, attributes and coordinate points, enforce consistency and quality standards, and then output the georeferenced information as Esri shapefiles and Geodatabases, Google Earth files, PDF reports and CSV files.
The engineering firm used one of its iPads, the GeoJot app and the GPS-Photo Link photo-mapping software to test the bundle as a viable mobile GIS data collection solution. For DLZ’s Nelson, the definitive proof that the firm had succeeded came when its crews created a series of pull-down menus to guide feature and attribute collection in the field. Compared to the GIS devices the firm had used previously, the list-generation function on the iPad data collection app was easy to use.
After confirming the practical benefits of using the iPad-based solution for GIS data collection and mapping in several pilots, DLZ bought additional Apple tablets and apps.