Drones: The Next Great Leap in Hydrography

Buy Guy T. Noll
Hydrographic charting is becoming more important outside the world of shipboard navigation as both industry and conservation have gone offshore to meet the increasing demands of a growing global population. By 2020, the subsea sector of oil exploration and extraction is expected to account for 20% of total crude oil production. In addition, global marine fisheries, which provide 15% of all animal protein consumed by humans, have been steadily collapsing for the last half century. As the needs of developed economies grow, so too must the tools to understand the new marine environments from which humanity seeks to satisfy those needs. Hydrographic surveys will become more valuable information resources as the survival of the planet and global prosperity become increasingly tied to the geography and ecosystem of the sea.
A Flawed Workflow
While the demand for hydrographic resources to assist emerging enterprises has increased dramatically over the last 30 years, the rate at which this data becomes available to key stakeholders has remained rooted in an outdated workflow that creates inefficiencies and delays. The construction of a hydrographic chart is a twofold process consisting of bathymetric readings taken from the surface and the complex step of gathering a shoreline compilation coordinated with the tide. Almost all surveys near coastal regions have typically been preceded by a coastal mapping effort. 
The purpose of this was to provide a frame of reference for the ocean data the hydrographer gathered at sea and also to establish and identify objects in the nearshore region that might be dangerous. However, up to now, there have only been two ways to obtain this crucial step in the creation of a topobathymetric dataset. A hydrographer might physically observe critical shoreline points with the aid of ellipsoidal-referenced bathymetry at high water or use an airplane with lidar to fly over the shore and take readings—called point-clouds—in clear waters or at low tide where possible. The first approach is slow and riddled with the potential for unsafe operations due to human error, and the second can be prohibitively expensive. Airplanes are also limited by where they can take off, airspace regulations and maneuverability. Shoreline areas that are remote, not easily accessible and which have rough terrain present obstacles for both ground-based and airborne shore mapping efforts. Additionally, if there is a change in the foreshore, such as manmade infrastructure, it can take months to observe again and correct inaccurate products.
A Seamless Integration
Drone technology itself has progressed over the past decade, allowing aerial photographic observation to become more accessible at a fraction of the cost of chartering aircraft for the same purpose. Fuel expenses alone can be an obstacle to obtaining aerial data. Drone integration with geographic information system (GIS) technologies has existed for several years. Using drones has proved to be a cost-effective and safe way to collect aerial data, with applications commonly used for fighting fire, monitoring environmental changes and managing rights-of-way vegetation. However, when users bring drone data into GIS, they exponentially increase the value of that data. And thanks to new innovations in drone technology, maritime users can exploit that integration in new and exciting ways. A seamless topobathymetric surface is now available to hydrographers interested in a more efficient and economical workflow.
Esri has just released the Drone2Map for ArcGIS app, which transforms high-resolution drone imagery into ready-to-use aerial data in the GIS platform. Users can bring point-clouds, mosaic datasets, 3D meshes and orthomosaics directly into the platform in near real time without any third-party application. This is a huge leap in hydrographic technology because users can instantly produce new observations to update nautical charts and topographic maps. Simple photographic data obtained from a miniature camera mounted on a drone can be used for point-cloud collection, rather than rely on airborne lidar. Additionally, a geospatial platform stores and manages Drone2Map data, provides authoring and publishing tools and streams live and authoritative data for rich situational awareness. Maritime organizations can see data on real-time maps and as 3D digital visualizations. Working in the online Esri platform, users can share drone datasets, maps and analyses with other departments and agencies as well as the public. 
The platform stores drone data for later use as well as creates 3D geospatial visualizations of the shoreline, piers and pipelines.
In addition to integrating point-clouds with bathymetric data, drone mapping is also applicable to incidents such as oil spill and chemical hazard response. For example, after an oil spill, drones capture situational imagery, and then GIS maps the affected area and uses oceanographic parameters—wind, currents, tide data—to project the spill’s drift over time. Emergency Operations Center staff use these reconnaissance maps to plan contingency response and deploy resources, such as for determining boom placement around the spill.
Drone2Map offers a seamless topobathymetric workflow that government agencies have invested years of research and vast amounts of money into developing. The value of this technology is not just the accuracy of the data itself, but the fact that Drone2Map liberates hydrographers in several ways. From an economic perspective, an inexpensive and accessible method of obtaining point-cloud data is invaluable. Drones are also more capable of maneuvering difficult terrain and aren’t limited by the same airspace standards as cumbersome aircraft outfitted with lidar. And drones also allow hydrographers to focus on their offshore bathymetry, as opposed to the additional risk of managing foreshore feature collection.
Why Improved Workflows Matter
This year, off the coast of Mexico, a Sistemas de Información Geográfica, S.A. de C.V. (SIGSA) boat was using multibeam echo sounder data collection to complement existing hydrographic survey data with detailed bathymetry. SIGSA spotted an uncharted buoy near a pier that would have posed a serious navigational risk to anyone using these charts. However, using Drone2Map, the hydrographic team was able to quickly and easily position it, and, through ArcGIS Online, send it to the Cartographic Department to update the current chart. This is a real-time, ground truth example of how drone technology has revolutionized workflows for hydrographers. This example, which could also have been an uncharted rock, a semisubmerged container or a small iceberg, shows how Drone2Map could save lives by ensuring that mariners are aware of all dangerous obstacles in their vicinity.
Moving forward, gaining a more accurate picture of the foreshore seabed will be crucial for a number of reasons. Pre-engineering technical hydrographic surveys are a necessary part of constructing nearshore structures. A complete hydrographic survey is also an important source of information in determining pollution sources and sedimentation rates and their impact on essential fish habitats such as kelp or coral reefs. Since nonlivestock protein sources, such as fish, present a possible solution to the challenge of cattle production’s effects on the climate, it is necessary to understand benthic and pelagic habitat impacts on recruitment rates in global fisheries. The increasing reliance on offshore energy such as wave generators and wind farms—which require cables to bring generated energy ashore—makes the need for fast and accurate nearshore hydrography imperative.
Drone technology opens up a world of possibilities in collecting data to complete a picture that was previously difficult and time-consuming to obtain and error-prone. With Drone2Map, shore-based information can be extracted very easily; and through ArcGIS Online, that information can be sent from the field to the office, and chart production can commence immediately. If there is any problem with the data, office-based team members can immediately send feedback to field technicians, who can resurvey without any delays. The valuable resource of hydrographic data is now more accessible and accurate. And it’s all thanks to a solution that can launch from the trunk of a car or the deck of a boat.
  • Today’s Energy Solutions, Manufacturing Group, Increased Drilling in Sub-sea to Push Demand for Floating Production Systems, http://www.onlinetes.com/article/off-shore-oil-exploration-floating-production-systems-071816/ (Jul 2016).
  • 2Camilo Mora et al., Management Effectiveness of the World’s Marine Fisheries, http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1000131 (Jun 2009).
The Author
Guy T. Noll is Maritime Principal Consultant at Esri.
(As published in the September 2016 edition of Marine Technology Reporter)
Marine Technology Magazine, page 24,  Sep 2016

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