Citizen Mapping and Charting (part 3)

Part 3: How the ‘Download Generation’ will Drive Electronic Charting in a New Direction
We are about to see an amazing transformation over the next decade, as the generation that grew up with the internet, wireless communication and geo-location starts to take over the work force. Never before has a generation had such a technological leap over their parents. As technologically savvy as ‘baby boomers’ perceive themselves to be, they are no match for their offspring. It is so common that parents defer to their offspring or grandchildren for technological guidance that it’s no longer a cliché or point of humour; it just “Is what it is”. This ‘download generation’ will change our charting... (read more)
2009-12-29 01:55:15

Improving Overall Resolution of Bathymetric Survey

Integrated Use of Multi-beam Echo Sounder and Towed Interferometric Sonar
Designing offshore engineering facilities requires large amounts of information. To acquire it, suites of engineering and geophysical surveys are run, which as a rule include such techniques of seabed and sub-bottom investigation as seismic profiling, acoustic, magnetic and bathymetric surveys. Obtaining accurate and detailed seabed bathymetry is extremely important because the quality of other surveys depends on the quality of the bathymetry. One of the most accurate and cost-effective ways to acquire high-resolution bathymetric data is the use of shipborne bathymetric systems such as multi-beam echo sounders (MBES) or interferometers. The drawback of this method is that the resolution of... (read more)
2012-04-19 03:50:13

Measuring the Uncertainty of a Swath Bathymetric Sonar

A Statistical Analysis for System Performance and IHO Compliance
In the last few decades, substantial efforts have been made to improve and facilitate the way hydrographic data is obtained. One technology is the EdgeTech 4600, an interferometric phase difference sonar. Unlike traditional interferometers, the EdgeTech 4600 is the first of its kind to offer complete swath coverage of the seafloor, even at nadir. Combining this kind of coverage with a vertical accuracy that exceeds IHO Special Order requirements in depths less than 30 metres, results in a sonar with superior area coverage rates, especially in shallow water. In the summer of 2012, bathymetric survey data was collected using an... (read more)
2013-05-23 02:50:53

Hydrographic Surveying: Where Do We Stand

The Ever-increasing Accuracy of Mapping the Surface Waters
Hydrographic surveying is highly specific and requires a suite of advanced acquisition and positioning sensors attached to a mobile survey platform as well as sophisticated software to allow the correct combination of all the data. For those within the industry, the advances over the last decade may feel more like an evolution rather than a revolution. If we look back one, two or even three decades, we can see the enormous leap hydrographic surveying has taken. Where do we stand, and what can we expect for the near future? In this article, we will look at the present compared to... (read more)
2018-12-11 02:51:31

The Study of Mapping the Seafloor

What is the Difference Between a Bathymetry Chart and a Hydrographic Chart?
This article will immerse you into the deep water of Bathymetry. It explains in detail what a bathymetry map is, what it shows, what methods we use to collect the bathymetry data and last but not least, how to create a good quality bathymetry map. It will also cover the difference between a bathymetry chart and a hydrographic chart and the techniques our ancestors used in the past to collect and record depths. What is Bathymetry? Bathymetry is the study of mapping the seafloor. Bathymetric maps represent the ocean (sea) depth as a function of geographical coordinates, just as topographic maps... (read more)
2019-01-15 08:58:54

Wave Radars

A comparison of concepts and techniques
Radar Remote Sensing of ocean surface waves may in general be defined as measuring characteristics of the sea surface by means of electromagnetic waves so that the sea surface is itself not disturbed. The electro-magnetic waves transmitted by the radar antenna are scattered back from the sea surface, modulated in amplitude and phase or frequency by the interaction with the sea surface in motion. This modulation carries information about sea-surface characteristics, surface waves and currents. Oceanographic data is extracted from the backscatter signal by sophisticated signal processing and data analysis. Why remote sensing? Surface ocean waves may be measured by... (read more)
2008-01-01 01:00:00

BlueTEC Texel

A Floating Tidal Energy Platform Prototype
Traditional solutions for generating electricity from the tides, where tidal turbines are installed on the seabed, require high-end offshore installation vessels and do not allow for easy access for maintenance. The BlueTEC floating tidal energy platform has a different approach. It is a permanently moored platform which generates renewable electricity from tidal currents by holding a tidal turbine underneath. The BlueTEC Texel is the first prototype and serves as a demonstration platform and is being used for R&D testing purposes. The project was realised through a partnership between companies active in the maritime and offshore industry; Bluewater, Damen Shipyards, Van... (read more)
2016-08-25 12:03:44

Depth of Cable Cover Gets New Look

New Technology Reduces Cost
Burying utility cables under the seabed in shallow water environments to ensure cable safety is accelerating because of green power generation initiatives and the relative ease of securing permits to lay cable in rivers or estuaries compared to onshore right-of-ways. In locations with shifting sands and bottom profiles, verification that the utility line remains covered is often required. A new remote sensing method has been developed to accomplish depth-of-cover utility surveys at greatly reduced cost. Maintaining underwater utility infrastructure varies with water depth. ROVs are generally used in deep water. In less than 50 metres, such as nearshore, estuaries, bays,... (read more)
2011-07-15 04:13:41

Lidar Seafloor Classification

New Application for HawkEye II Airborne Lidar System
Airborne Lidar (Light Detecting and Ranging) is a well-established remote sensing technique which scans the terrain and seafloor with high-frequency laser pulses. Until now, bathymetric Lidar data has been processed to generate marine depth information and seafloor topography. However, Airborne Hydrography AB (AHAB) has developed a new method of processing data which allows information about the actual properties of the seafloor to be extracted. The accuracy and efficiency of reflectance imaging for seafloor classification is demonstrated here with data from coastal sites in both Massachusetts and Sweden. By Xin Liu, Andreas Axelsson and H. Michael Tulldahl, Sweden. With its advantage... (read more)
2011-05-17 04:02:56

Submarine Volcanoes and Autonomous Survey Vehicles

Fringed by deep trenches, Japan is a country composed of seismic and volcanic active island arcs, where the huge Pacific Plate and the smaller Philippine Sea Plate converge to the Eurasian Plate. Integration of tectonic and volcanic activity since the geological Tertiary period formed beautiful mountainous landscapes and scattered small plains with rich soil. At sea around Japan, two volcanic ridges are extending to south and southwest from the mainland Japan. It means Japanese waters are not free from volcanic hazards. In the morning of 17 September 1952, the Chief Hydrographer of Japan received a telegram from a fishing boat... (read more)
2008-01-01 01:00:00
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