NOAA Ship Fairweather uses new technology to improve survey efficiency

By ENS Peter Siegenthaler

Following the scheduled winter repair period, Fairweather is kicking off the 2017 field season in Tlevak Strait; the waterway between Dall Island and Prince of Wales Island in Southeast Alaska. This area was last surveyed between 1900 and 1939, and the lead-lines used at the time to determine depths were susceptible to omission of rocks and other features in an area. Using the latest innovations in hydrographic technology, Fairweather will be resurveying these areas with complete coverage multibeam echo sounder bathymetry. This allows Fairweather to identify any rocks or shoal features missed in prior surveys, increasing the safety for local communities, whose economies and livelihoods are dependent on maritime transportation of goods.

One of the new developments Fairweather’s survey department in particular is excited about is a new software program affectionately named “Charlene.” Charlene was developed by PS Eric Younkin at Coast Survey’s Hydrographic Systems and Technologies Branch (HSTB) to automate the night processing workflow. This simplifies hours spent each night converting and correcting raw sonar data into an automated script which takes in raw data at one end and generates products at the other. Initial results are promising, and the ship is looking forward to fully integrating Charlene into the processing workflow.

Another new development for the 2017 field season is new multibeam sonars for the ship’s survey launches, which were installed during the winter repair period. The preliminary data acquired by these sonars has shown vast improvement over their predecessors’ data, which will go a long way towards reducing data processing timelines. The new sonars do this by automating most of the acquisition parameters in real-time, far faster and more effectively than could be achieved manually. They also take advantage of a multitude of hardware and software advances that have taken place over the past several years, resulting in systems that are quieter, smaller, and easier to operate.

Fairweather is continuing to use and develop the launch-mounted lidar systems (lasers) for the acquisition of shoreline data. This was another HSTB-developed process that was validated during the 2016 field season. This year, Fairweather is using those lessons learned in order to further improve our acquisition workflow. These systems create accurate real-time point clouds of features above the waterline and have revolutionized the way hazards to navigation are documented. Before the use of lasers, shoreline verification frequently required physically touching rocks and obstructions above the water surface for accurate measurement and placement. This process involved increased risk, took more time, and produced less accurate data. The new laser workflow addresses all these limitations. By scanning the shoreline at a distance with calibrated equipment, efficiency, accuracy, and safety are all greatly improved.

Overall, Fairweather is enthusiastic about being back at work in Alaska. With her new software, sonar systems, and dedicated crew, the stage is set for and productive field season!

Area surveyed by Fairweather May 30- June 10, 2017.
Area surveyed by Fairweather May 30- June 10, 2017.

NOAA Ship Rainier surveys the waters around Kodiak Island

kodiak-ais
Concentration of automatic identification system (AIS) traffic around Kodiak Island. Green is a low concentration, yellow is medium concentration, red is high concentration. Notice the approaches to Port of Kodiak show high traffic.
by ENS Michelle Levano

Kodiak Island is the 2nd largest island in the United States; it is part of the Kodiak Island Archipelago, a group of islands roughly the size of Connecticut. Due to the island’s location in the Gulf of Alaska and North Pacific Ocean, Kodiak is ranked as third in commercial fishing ports in the U.S. in terms of value of seafood landed. In 2015, the Port of Kodiak was responsible for 514 million pounds of fish and $138 million of product. More than one-third of the jobs in Kodiak are related to the fishing industry.

The Port of Kodiak is home to more than 700 commercial fishing vessels, and has more than 650 boat slips and three commercial piers that can dock vessels up to 1,000 feet. In addition to fishing, Kodiak is the hub of the Gulf of Alaska container logistics system, serving the southwest Alaskan communities with consumer goods and outbound access to the world’s fish markets.

In order to access all the Port of Kodiak has to offer, vessels must first travel through Chiniak Bay, which was last surveyed as far back as 1933 via wire drag (see details in the Descriptive Report for the Wire Drag survey of Women’s Bay and St. Paul Harbor).

Today, we are going over the same areas and surveying them utilizing multibeam echo sounders to collect bathymetric soundings that measure the depth of the seafloor.

This year, Rainier is surveying the approaches to Chiniak Bay, covering the following areas: South of Spruce Island, Long Island, Middle Bay, Kalsin Bay, Isthmus Bay, Cape Chiniak, and offshore of Cape Chiniak.

Since arriving on project, Rainier has been busy surveying these areas, confirming what has already been charted, updating with more accurate depths, and finding some new features for the charts along the way!  So far Rainier has patch-tested her launches to ensure survey accuracy, started work on Long Island and Kalsin Bay surveys, and established a global navigation satellite system (GNSS) base station to gain a higher positioning accuracy.

Rainier will continue to survey this area of Kodiak until mid-June. Check back on the Coast Survey blog for more status updates. Interested in visiting the ship? Rainier‘s crew will be offering tours on May 27, from 1 p.m. to 4 p.m. and May 28, from 10 a.m. to 2 p.m., at the city pier in downtown Kodiak.

Please contact NOAA Ship Rainier’s public relations officer at michelle.levano@noaa.gov for more information.

kodiak
Rainier‘s bathymetric survey coverage since March 29, 2017. The multicolored areas show where Rainer surveyed using multibeam bathymetry. The blue dashed areas show where Rainier intends to survey this year.

Beta test of crowdsourced bathymetry holds promise for improving U.S. nautical charts

We are on the verge of acquiring a significant new source of data to improve NOAA nautical charts, thanks to an enthusiastic industry and mariners equipped with new technology.

By Lt. Adam Reed, Integrated Oceans and Coastal Mapping (IOCM) Assistant Coordinator

The United States has about 3,400,000 square nautical miles of water within our coastal and Great Lakes jurisdiction. Coast Survey, who is responsible for charting that vast area, averages about 3,000 square nautical miles of hydrographic surveying each year. The data collected by those surveys update over a thousand NOAA charts. However, hydrographic surveys are expensive and laborious, and so Coast Survey directs them toward the highest priority sites, which leaves many coastal areas without updates for many years.

Coast Survey may soon get new sources of information, provided voluntarily by mariners, which will alert cartographers to areas where shoaling and other changes to the seafloor have made the chart inaccurate.

Rose Point Navigation System beta tests new crowdsourcing database

Technology has reached the point where any boater can buy an echo sounder kit, add a GPS system, record depth measurements, and make their own geospatial observations in a common reference frame. The question then for hydrographic offices (who are concerned with improving nautical charts for safe navigation) becomes “how do we take advantage of that?”

Rose Point Navigation Systems is working with system developers at NOAA’s National Centers for Environmental Information (NCEI) and with hydrographic experts at Coast Survey and others who are collaborating on an international effort to maintain crowdsourced bathymetry. In a beta test released on May 13, 2016, Rose Point has added a new feature to Coastal Explorer that gives users an option to send anonymous GPS position and soundings data to a new international database managed by NCEI. After getting permission from users, Rose Point systems will generate data log files of positions, depths, and time, and automatically transmit the files to the data center, where Coast Survey can pull the data to compare it to nautical charts.

Crowdsourced bathymetry is an international project

Using data from private sources is not new for Coast Survey. Private interactive cruising guides and other internet-based enterprises have set up services that allow commercial mariners and recreational boaters to share information about navigation hazards they see (or experience) while on the water. The United States Power Squadrons and the U.S. Coast Guard Auxiliary have a decades-long tradition of sharing updates through our cooperative charting programs. But the lack of appropriate software and integration between sources has hampered efforts to use the information to its full potential.

Hydrographic offices around the world are re-thinking crowdsourced bathymetry. In October 2014, Coast Survey led the U.S. delegation to the Fifth Extraordinary International Hydrographic Conference, with Rear Admiral Gerd Glang at the helm. At this meeting, the U.S. and France jointly proposed an initiative (see Proposal No. 4) that introduced crowdsourced bathymetry as a recognized source of data for nautical charts. One of the results of that initiative was the formation of the IHO Crowdsourced Bathymetry Working Group (IHO CSBWG) that set out to develop crowdsourcing principles and guidelines, and then offer a platform for sharing best practices around the world.

Working hand-in-hand with NCEI, the working group has developed a database that can receive volunteered bathymetric data. Data can come from anyone in the world, and everyone can access it.

Coast Survey will use crowdsourced bathymetry to assess chart accuracy

Crowdsourced reports serve an important role in focusing attention on trouble areas. The data helps cartographers determine whether a charted area needs to be re-surveyed, or if they can make changes based on the information at hand. Even with very sparse data, cartographers can make improvements to nautical charts.

Agreeing in principle to use crowdsourced data is much different than applying the system to the vigor of data transmission from moving vessels, however, so Coast Survey experts contributed hydrographic expertise and system testing. Using Rose Point’s Coastal Explorer, Coast Survey Research Vessel Bay Hydro II transmitted “crowdsourced” data using log files that were automatically produced by the electronic charting system software. (Bay Hydro II is Coast Survey’s primary platform to test and evaluate new hydrographic survey technologies.)

BHII bathymetric data collection
Coast Survey Research Vessel Bay Hydro II collected about 123,000 soundings, over 12 days, to pre-test the efficacy of Rose Point beta test for bathymetric crowdsourcing.

“When you aggregate crowdsourced data, we can expect to see trends develop where the seafloor has likely changed from charted data,” explains Lt. Anthony Klemm. “Using Bay Hydro II data transmissions, we saw such trends indicating shoaling near the Patuxent river entrance. Similarly, in the approach to Solomons harbor, trends displayed depths deeper than charted.”

It is important to emphasize that Coast Survey does not necessarily make changes to any significant charted feature based on crowdsourced data alone. That data, however, is about to become a major factor in making charts better.

Studying the use of satellite-derived bathymetry as a new survey tool

by Ensign Kaitlyn Seberger, onboard NOAA Ship Thomas Jefferson

Nautical charts are an important tool in navigating safely in coastal waters, and Coast Survey’s mission is to keep these charts up to date. However, maintaining accurate charts can be a challenge in locations where sandy shoals may shift seasonally and present a danger to navigation. These areas differ from the current nautical charts, and bottom contours change so rapidly that it may seem an impossible task to keep up using the traditional survey methods. Office of Coast Survey and NOAA Ship Thomas Jefferson are seeking a solution to this ongoing problem and may have an answer with satellite-derived bathymetry.

Satellite-derived bathymetry (SDB) begins with using multi-spectral satellite imagery, obtained by satellites such as Landsat and WorldView2, which compares green and blue color bands.

Multi-spectral satellite imagery of Mutton Shoal in Nantucket Sound, overlaid on the chart.
Multi-spectral satellite imagery of Mutton Shoal in Nantucket Sound, overlaid on the chart.

Green color bands are attenuated by the water faster than blue bands and help to infer relative depths of the water (blue areas being deeper than green). These images are then transformed into a color range scale applicable to the color scale used when surveying with a multibeam echo sounder. With the color range applied, reds on the image represent an area that may be shoal whereas blues and greens represent deeper water.

Satellite-derived bathymetry of Mutton Shoal with a color range scale that is correlated with the color scale used for multibeam processing
Satellite-derived bathymetry of Mutton Shoal with a color range scale that is correlated with the color scale used for multibeam processing.

Since the images are based on attenuation of color bands, depth can only be inferred, so survey equipment (such as vertical beam and multibeam sonars) is necessary to acquire true depth.

This fall, NOAA Ship Thomas Jefferson investigated the use of satellite-derived bathymetry imagery as a new survey tool. Survey technicians will calibrate the application of this imagery through bathymetry studies for Nantucket Sound and Chincoteague Island. NOAA Lt. Anthony Klemm, who is leading the studies, chose these project areas because they both had relatively clear shallow water and were in a highly changeable area. At these locations, he chose specific shoals for exploration based on vessel traffic density.

In October, Thomas Jefferson spent two days in Nantucket Sound researching shifting shoals using the satellite-derived imagery overlain on the most recent chart. Ensign Marybeth Head developed line plans to acquire data over the potential location of shoals as seen with the satellite images, as well as their charted locations. Survey launches acquired multibeam data in water deeper than six feet, and Z-Boats were sent in to acquire vertical beam data in areas too shoal for the launches to safely operate.

The video shows Z-boat surveying alongside the launch in shoals too shallow for the launches to operate safely. (Video credit: ENS Head)

Satellite-derived bathymetry of Mutton Shoal with multibeam data from the investigation overlaid. This picture demonstrates how accurate the location of the shifted shoal was compared to the SDB imagery.
Satellite-derived bathymetry of Mutton Shoal with multibeam data from the investigation overlaid. This picture demonstrates how accurate the location of the shifted shoal was compared to the SDB imagery.

During routine conductivity, temperature, and depth casts for sound speed velocity, Ensign Head and Ensign Kaitlyn Seberger used a Secchi disk to determine the attenuation coefficient at each cast location for later comparisons.

The satellite imagery was a vital tool in project planning, as well as determining safe navigation of the ship and the survey launches. Below is a picture of the chart location where Thomas Jefferson intended to anchor. The adjacent image is the satellite-derived bathymetry imagery indicating the anchorage would have been within a shoal area and unsafe for anchoring.

Side-by-side picture of the chart and SDB imagery for the intended anchorage location in Nantucket Sound. SDB imagery indicated a shoal that covered half of the anchorage safety circle. A Z-boat verified the indicated shoal was almost 30 ft shoaler than charted and without this useful imagery, the ship and launches could have run aground.
Side-by-side picture of the chart and SDB imagery for the intended anchorage location in Nantucket Sound. SDB imagery indicated a shoal that covered half of the anchorage safety circle. A Z-boat verified the indicated shoal was almost 30 ft shoaler than charted and without this useful imagery, the ship and launches could have run aground.

Ensign Head determined safe passage routes for the survey launches, using the satellite-derived bathymetry imagery overlaid on a chart of the area, as the charted soundings were not reliable. For example, a safe passage route between the study areas and the ship was located between two shoals that had shifted considerably from the chart of the area. Sections of the passage are currently charted at 20 feet or more of water, but the fathometer on the launch displayed depths of less than 10 feet.

Boat sheet for the launches indicating a potential safe passage route from the project area to the ship.
Boat sheet for the launches indicating a potential safe passage route from the project area to the ship.

After processing the multibeam data, Ensign Head determined that more than half of the charted shoals in the project area had shifted and the red zones depicted in the satellite-derived bathymetry imagery were significantly shoaler than charted depths for the surrounding area. Results from the investigation showed that the satellite-derived bathymetry for Nantucket Sound was exceptionally accurate and aided in the identification of current navigational dangers.

However, more research is needed regarding the use of satellite-derived bathymetry as a contemporary survey method. Limitations on use of the imagery can include variables such as cloud cover, turbidity, Chlorophyll a, and other water quality properties that may affect attenuation. Despite these challenges, satellite-derived bathymetry is a new tool that could support survey efforts by reducing the amount of time and area necessary to survey and by increasing the effectiveness of NOAA’s efforts to efficiently provide safe navigation to the local mariner.

Explore once, use many times

This post is adapted from a poster at the U.S. Hydro 2015 conference, in National Harbor, Maryland.

Pilot project shows nautical charting applications using NOAA Ship Okeanos Explorer data

By
James J. Miller and Tyanne Faulkes, physical scientists, NOAA Office of Coast Survey, Atlantic Hydrographic Branch
Lindsay McKenna, physical scientist, ERT Inc. contractor with the NOAA Office of Ocean Exploration and Research

Mapping is the foundation of ocean exploration and marine spatial planning. In its mission to explore and broaden our knowledge of the oceans, the NOAA Ship Okeanos Explorer has collected high-resolution multibeam data as an integral part of its operations around the globe. Since 2013, the Office of Coast Survey has collaborated with the Okeanos Explorer during their expeditions, to improve hydrographic acquisition and processing methods and expand multibeam coverage in the Gulf of Mexico and Atlantic Ocean. The resulting bathymetry has supported a diverse array of oceanic research and contributed to the protection of ecologically critical habitats in U.S. waters.

A new initiative between the Office of Ocean Exploration and Research and Coast Survey has opened the door to further maximizing the data’s usefulness. In alignment with NOAA’s integrated ocean and coastal mapping program’s philosophy of “map once, use many times,” this pilot project will integrate Okeanos Explorer multibeam data from the Gulf of Mexico into NOAA’s nautical chart update pipeline, and will expand in the future to incorporate data from the Atlantic and Pacific Oceans.

Pilot Project

Two surveys were identified during the Okeanos Explorer’s 2014 field season for a pilot project.

OE Survey W00286The focus of expedition EX1402L1 (Survey W00286) was to test the vessel’s operational equipment and map the Florida Escarpment west of the Florida Keys.

OE Survey W00285The primary goal of expedition EX1402L2 (Survey W00285) was to map the region southwest of the Flower Garden Banks National Marine Sanctuary and provide details to the scientific community about biological habitats in the area.

Office of Coast Survey personnel provided field support and assisted with data analysis and documentation during these expeditions. Although it was not the original intent of these two surveys, Coast Survey assessed the data to determine whether it would improve the nautical charts in the project area. The source diagrams for the affected charts (11340, 11420, 11006, and 11013) showed that the sparsely charted soundings were based on partial coverage surveys dating from pre-1900 to 1939. In contrast, the Okeanos Explorer used a modern multibeam echo sounder (Kongsberg EM302) to acquire data with nearly complete coverage. Further analysis indicated that the Okeanos Explorer soundings were generally shallower than the charted soundings, in some instances by greater than 500 meters.

Once it was demonstrated that the Okeanos Explorer’s multibeam bathymetry would significantly improve the charts, the Atlantic Hydrographic Branch incorporated the data into Coast Survey’s chart update pipeline. Branch personnel have applied uncertainty to the data, created CUBE surfaces, written descriptive reports to document the acquisition and processing methods, and conducted a survey acceptance review to ensure that the data meets the relevant NOAA specifications for nautical charting. Coast Survey is currently compiling the data to update the affected charts.

Remaining Challenges

The various sources of the Okeanos Explorer’s vertical uncertainty need to be better accounted for within the CARIS total propagated uncertainty computation. These include tide uncertainty and sound velocity corrections (expendable bathythermographs).

In addition to the surveys already being evaluated, there is an additional 60,000 square nautical miles of Okeanos Explorer data along the Pacific Coast and Hawaii that can potentially be used for nautical charting.

Beyond the pilot: applying more Okeanos Explorer data to charts

The Atlantic Hydrographic Branch is evaluating Okeanos Explorer data that covers over 62,000 square nautical miles in the Atlantic Ocean and the Gulf of Mexico. (The surveyed area is larger than the land area of Kansas!) Coast Survey would like to use the data to update over 30 nautical charts.

Atlantic Hydrographic Branch’s physical scientists will continue to collaborate with the Okeanos Explorer and the Office of Ocean Exploration and Research to provide support, improve data acquisition and processing methods, and transfer data from the ship for chart compilation.

About the NOAA Ship Okeanos Explorer

Commissioned in August 2008, the NOAA Ship Okeanos Explorer is the nation’s only federal vessel dedicated to ocean exploration. With 95% of the world’s oceans left unexplored, the ship’s unique combination of scientific and technological tools positions it to explore new areas of our largely unknown ocean. These explorations will generate scientific questions leading to further scientific inquiries.

Through the Okeanos Explorer Program, NOAA’s Office of Ocean Exploration and Research provides the nation with important capabilities to discover and investigate new ocean areas and phenomena, conduct the basic research required to document discoveries, and seamlessly disseminate data and information-rich products to a multitude of users. The program strives to develop technological solutions and innovative applications to critical problems in undersea exploration and to provide resources for developing, testing, and transitioning solutions to meet these needs.