“For collection of lower precision assets, to be added new to the GIS we will pair the R2 with an iPad or our Trimble T10 tablet and run Esri® Collector®,” said Milanes. “All of our field tablets have cellular connectivity, with SIM cards and built-in cell modems. We connect to our local VRS network for real-time corrections; this gets us the sub-foot precision we need.” Es² performs a wide range of projects for the port, other public sec- tor entities, and private sector clients as well. Different mapping tasks call for different precision thresholds. For higher precision mapping, Milanes likes to use Trimble Access™ (survey software on a tablet) to collect and analyze the GNSS observations. And for instances where GNSS might not work well—limited sky view under trees, or mul- tipath from cranes and structures— Es² has a Trimble S5 robotic total station and will process data in the Trimble Business Center (TBC) Port NOLA has been quite pleased with this first mapping phase and has recently put out a request for proposal (RFP) for the next phase. The goal is to continue to convert existing records, ground-truth these via field mapping, and perform new mapping with high-precision GNSS paired with user-friendly mobile apps. A web portal then serves up these updated GIS datasets for the entire enterprise. While there may be one or more mapping phases ahead, Cloos does not anticipate having dedicated staff for long-term ongoing mapping. “We'd like to move to where we can build capacity for our staff, train them how to fit this into existing workflows, support them with [GNSS] and mobile apps on tablets they can use in the course of their daily operations. We’ve already had great success with apps like Esri Survey123 and GNSS. The information can be entered, verified, and troubleshot right there in the field.” surveying office software. Results and Next Steps Port NOLA authored their Esri Collector app for the fixed asset mapping, verification, and update. The software was deployed with field mapping teams on Trimble T10 tablets with Trimble R2 GNSS receivers.
Services, Inc. (Es²). Andrew Milanes, PE, GISP, is the vice president of Es². “The contract evolved,” said Milanes, “particularly with regards to the NOPB. When we would ask for existing records, we might only find paper maps that were typically only construction drawings, and not proper as-builts. Some of the newer records were CAD drawings, but those were few, and we would find some that would not agree with others done only years or months prior.” It became apparent to Es² and the port that new mapping and field data collection would be necessary to validate existing records, and to fill in substantial data gaps. “We were able to do heads-up digitizing of much of the rail infrastruc- ture, switches, etc., with digital orthophotos from various sources,” said Milanes, “but it was not possible to capture everything.” This is where the expertise and field equipment that Es² had would play a major role. Milanes added, “By the time we made the effort to try to digitize paper maps, geo-reference those and merge with features gathered from aerial photos, we would find a lot of uncertainty in the data. Field mapping was the only way we could be sure.” And for Es², that meant using the Trimble R2 GNSS receiver and antenna. Mila- nes explained that this system had already proven its flexibility as the GNSS component of mapping kits for a variety of projects. Mapping Kit The Trimble R2 rover was designed with asset mapping in mind but can often achieve similar precisions to that of its surveying cousins. Typically mounted on a 2 m surveyor’s pole (as Es²’s crews did) the ruggedized R2 is located over the mapper’s head to enable a clearer view of the sky. Milanes said that in clear sky conditions, they were comfortably achieving 0.1’ (3 cm) horizontal precisions. “The cool thing is that using the same equipment, and software, and in the same amount of time we got high precision on everything—it is great to know we got it right the first time.” Brennon Albarez (left), field technician, and Andrew Milanes (center), VP of Es², consultants for the mapping pilot with Maggie Cloos (right), Port NOLA GIS manager on the railroad portion of the Huey P. Long Bridge over the Mississippi River. The team collected fixed asset features for the New Orleans Public Belt Railroad, such as rail line expansion joints and signals, using a Trimble R2 and T10 tablet with Esri Collector.
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may 2020
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