Southampton uses customized mobile GIS/GPS solution to streamline field data collection
Nat Norton, Manager, Corporate GIS Services, Vanasse Hangen Brustlin, Inc., Watertown, Massachusetts
Annette DesRochers, GIS Manager, Town of Southampton, New York
Geographic Information System (GIS) technology is recognized as a powerful data creation and analysis tool that helps governments perform a variety of diverse tasks, from developing and maintaining infrastructure to complying with environmental regulations and fighting crime. Global Positioning System (GPS) technology is a popular and timesaving navigation tool that is fast becoming a fixture in cars, boats, planes and handheld computers. Both of these technologies can help governments run more efficiently; however, they are often used independently of each other. GIS is most commonly associated with in-office use, and GPS is recognized as a field data collection tool and navigation device.
Until now, a common data collection practice has been to use GPS in the field to collect point data, bring it into the office, export it to a format that can be read by a GIS software system, and import it into GIS. Once imported into GIS, skilled personnel must manipulate the data to combine newly collected or modified data with existing information.
Sound complicated? Like a duplication of effort? That may be true if you are using GIS for in-house data creation, analysis and management and are using traditional GPS data collection methods in the field. In today's economy with cities and towns struggling to maintain funding levels, maximizing efficiency to conserve resources is key.
The availability of mobile GIS software that can run on small handheld Pocket PCs is streamlining this process and changing the way data is collected. This mobile software combined with integrated GPS data receivers now permits asset managers to bring their GIS inventories directly into the field for data collection, verification and modification.
Using this method, both location and attribute data attached to physical features can be managed simultaneously. The same GIS software that is available in the office is also used in the field with the added benefits that GPS brings to the field data collection process.
The Town of Southampton, New York recently used this method to edit and verify its stormwater collection system. Located 75 miles east of New York City on the South Fork of Long Island, it is a world away from its metropolis neighbor. This small rural town, made up of six quaint villages and bound by beautiful beaches, is a favorite summertime getaway for city dwellers. The year-round population is just under 55,000, although that number significantly increases as the thermometer rises. Despite its "small town" nature, the Town of Southampton is commonly considered throughout Long Island to be a pioneer of implementing sophisticated technologies.
All storm drain outfalls must be mapped.
Southampton started an Infrastructure Management System project in 1999. The primary focus of the system was to collect, evaluate and manage pavement condition data town-wide. Also included in the project was the development of a process for the Town to collect drainage and utility data in order to meet pending GASB-34 financial reporting requirements.
In 2002 the focus on drainage outfall locations became a priority as the Environmental Protection Agency's Phase II regulations expanded the NPDES program to include small municipal separate storm sewer systems.
The Town's GIS Division started by reviewing existing as-built plans and digitizing drainage surface features such as catch basins and manholes. The process involved scanning and digitizing information from the plans using ESRI ArcGIS software. Data entry forms were created to facilitate the capture of drainage structure attributes as they were digitized. This data was captured and stored in an ESRI shapefile. After the Town digitized much of its existing records, estimated at approximately 10-20% of the entire Town's existing infrastructure, it was time to develop a methodology for field verification and location of structures not recorded on existing plans. This also included recording the location of all outfalls to open water bodies as required by NPDES Phase II regulations.
Available high-resolution orthorectified aerials proved to be an ideal background data layer
Field data collection pilot project
The GIS and Highway Departments worked together with the Town's GIS and Asset Management consultants to develop an efficient approach to collecting this field data. They chose ESRI's ArcPAD software, which was customized by its consultant and integrated with GPS to streamline the collection process. This solution best fit their needs. They could "check out" pertinent GIS data from their network file server and load it onto handheld Pocket PCs. It would also include background data layers from the Town's GIS inventory. The combination of having a GIS inventory on a handheld loaded with background data layers and the use of GPS would prove to be very effective.
The GIS and Highway Department staff reviewed available town-wide GIS data to determine the most appropriate background layers to bring into the field. A decision was made to use the color digital orthophotographs provided by the State of New York. They were then trained by the Town's consultant to use the mobile data collection software. The training included in-office instruction on how to "check out" data for field collection, conduct GPS mission planning, and connect to a GPS data receiver to verify, modify, add and possibly delete information as found in the field.
Necessary equipment used for the pilot project included a Compaq Ipaq Pocket PC with an extended battery pack and additional disk space capable of storing the orthophotographs and a Trimble Pro-XR sub-meter GPS receiver.
Field data collection process
The Town selected a typical representative neighborhood and began the field data collection process. Town personnel walked streets stopping at manhole and catch basin locations. Each drainage structure location was verified, moved or created to capture its true field location, description, and condition in the GIS database. The structure locations were verified using GPS, and structure attributes were entered through custom-developed forms. The user has the ability to select values from pull-down lists and enter new values if necessary to the lists in the field. Digital pictures can be captured and linked to each physical feature in the field.
After each day of field data collection, the stormwater data was copied back to the Town's network file server and "checked in." The customized element of the software, created by the Town's consultant, synchronized the data collected and/or modified in the field. Every data point that was "checked out" for data collection was tested by the application to determine if any of its many attributes were modified or if the location was changed. The newly-collected data and updated inventory were written back to the master database along with the date, data collector and method of location (GPS or digitized).
Now that the field data collection process has been defined and the software is in place, field data collection hardware is being purchased and the GIS staff can transition into more of a support role for the Highway Department. Highway Department personnel familiar with the Town's drainage system with no previous GIS experience will use the system to proceed with data collection town-wide. This approach has allowed the Town to do more with their own personnel and spend less. The hands-on GIS approach used by Town of Southampton is consistent with other Town department-specific GIS applications that have been developed with the end user in mind.
For more information, contact Nat Norton at (617) 571-4187 or firstname.lastname@example.org.