Use of Advanced Geospatial Data, Tools, Technologies, and Information in Department of Transportation Projects (2013) / Chapter Skim
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Pages 32-50
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32 Public safety aspects related to geospatial data, tools, and techniques deserve the highest concern. Virtually all systems evaluated in this work are able to obtain parameters important to increased safety on roadways (e.g., sign placement, bridge clearances, and lane and shoulder widths)
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33 rain model (DTM)
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34 Close-Range Photogrammetry The New Mexico DOT found beneficial results in a pilot study involving close-range digital photogrammetry for remote bridge inspections and 3D modeling of historic bridges. The cost for this work typically is competitive with that of other methods (Jáuregui et al.
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35 Current Uses of Satellite Imagery in Transportation Currently, satellite imagery provides the background for numerous map applications. Several states provide general or statespecific satellite image links, connecting the viewer directly to these websites.
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36 air-based, and ground traffic counts. It was determined that satellite or air-based images of the necessary spatial resolution would give accurate results but not be cost-effective at the time of print of this report (McCord et al.
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37 ing point clouds. Two major formats exist for data exchange between packages.
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38 Sampling intervals for LIDAR are also not uniform. The resolution will degrade with distance from the scanner.
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39 The Washington DOT evaluated the integration and efficiency achievable in transportation workflows with LIDAR data. This report started with a pilot study aimed at determining the benefits of LIDAR in transportation workflows, specifically in feature extraction.
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40 for horizontal accuracy QC, but also for splicing ALS strips. Results from this ongoing study determined that with a combination of careful flight planning, adequate processing, and QA/QC methods, results could be obtained with 1–2 cm and 5 cm accuracies in the vertical and horizontal, respectively (Toth and Brzezinska 2009)
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41 A study of early sinkhole detection using ALS was conducted for the Florida DOT. This study did not show ALS was a feasible option for this task.
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42 Conversely, RTK systems use a base station and one or more rovers. Base receivers obtain signals from the satellites carrier signal, rectify these signals to gain geospatial position, then broadcast the corrections to the rovers through ultrahigh frequency, or some other type of frequency.
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43 sky, and quality degrades when trees, buildings, and such obstruct this view. Current Uses of GNSS in Transportation NCHRP Synthesis 301 discusses the integration of GPS into GIS, including common problems and solutions.
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44 THREE-DIMENSIONAL MODEL-BASED DESIGN Historically, highway design has been done in a 2D drawing environment, first manual and then digital, or CAD. This 2D approach involved a number of sequential steps that resulted in plan/profile drawings and cross sections typically at 50-foot intervals.
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45 They are utilizing high-resolution photography and proprietary software to create this workspace. This has allowed them to conduct routine bridge inspection remotely and help inspectors get familiar with sites before visiting.
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46 grade a site without ever having to drive stakes. All grading is done entirely through equipment guided by GPS and a base model created from the 3D point cloud.
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47 technology to alleviate such hindrances by states including New Hampshire, Ohio, Texas, Maine, and Mississippi. These projects have continually shown progressive results in terms of speed, accuracy, and ease of use gaining and using gathered data.
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48 UNMANNED AIRBORNE VEHICLES UAVs, also known as unmanned aircraft systems (UASs) , are airborne vehicles (small planes, helicopters, or hybrids)
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49 ing benefits were found to exist and be of use to transportation agencies. These benefits are not possible to achieve, however, owing to the restriction of airspace under FAA guidelines, liability issues in the event of a crash, and to a lesser extent, system costs, and privacy issues (McCormack 2008)
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50 traffic metrics, current conditions, construction progress, and emergency response situations. As shown in Table 1, 90% of DOTs consider video logging the state of the practice.
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