A two-part process for assessing the adequacy of hydrographic surveys and nautical chart coverage

IHO Publication C-55 contains information about the progress of hydrographic surveying and nautical charting for littoral states. Listed primarily as percent coverage, it is difficult to use this information to determine: 1) if the current level of surveying or charting is adequate or in need of action, or 2) can be used to compare different locations. An analysis methodology has been developed to assess the adequacy of hydrographic surveying and nautical charting coverage. Indications of chart adequacy as depicted on charts or sailing directions are spatially correlated with significant maritime areas associated with navigational/national interest. However, an analysis based solely on these datasets is limited without access to the current depth information. Publically-available, multi-spectral satellite imagery can be used to derive estimates of bathymetry and provide information in previously unsurveyed areas. Preliminary results show that multi-spectral satellite remote sensing is potentially beneficial as a reconnaissance tool prior to a hydrographic survey

Satellite-Derived Bathymetry a Reconnaissance Tool for Hydrography

In some developing countries, the information available to plan and prioritise hydrographic surveys is typically based on visual inspection of existing nautical charts. However, due to the age of many existing charts and lack of availability of the original source data from which they were compiled (e.g., smooth sheets) this type of analysis is often quite limited. A study was conducted to evaluate the use of a satellite-derived bathymetry (SDB) procedure to map shallow-water bathymetry in a GIS environment, and to identify areas that require a new hydrographic survey. Publically available, multispectral satellite imagery and published algorithms are used to derive estimates of the bathymetry. The study results indicate a potential use of the procedure by national hydrographic offices as a reconnaissance too

Beyond the Chart: The use of Satellite Remote Sensing for Assessing the Adequacy and Completeness Information

Chart adequacy and completeness information consists of the symbols, abbreviations and warnings used to inform mariners of the level of confidence that should be given to data on a nautical chart. This information is derived both from the nautical chart and sailing directions. However, analysis based solely on these datasets is limited without access to the sources (e.g., smooth sheets). Publically-available, multi-spectral satellite imagery and published algorithms can be used to derive estimates of the relative bathymetry in shallow, clear waters. In this study, we evaluate the potential of these methods for supplementing the procedure to assess the adequacy of hydrographic surveying and nautical charting coverage. Optically-derived bathymetry provides information in areas that have not been surveyed and monitor any seafloor changes that may have occurred since the last survey of the area. Preliminary results show that multi-spectral satellite remote sensing is also potentially beneficial as a reconnaissance tool prior to a hydrographic acoustic survey

Development of a Geo-spatial Analysis Methodology for Assessing the Adequacy of Hydrographic Surveying and Nautical Charts

IHO Publication C-55 (Status of Hydrographic Surveying and Nautical Charting Worldwide) contains information about the progress of hydrographic surveying and nautical charting for a country with navigable waters under its jurisdiction. Listed primarily as percent coverage, it is difficult to use this information to determine: 1) if the current level of surveying or charting is adequate or in need of action, or 2) can be used to compare different locations. An analysis and assessment methodology has been developed to assess the adequacy hydrographic surveying and nautical charting coverage. Indications of chart adequacy and completeness as depicted on current charts or sailing directions are spatially correlated with significant maritime sites/areas associated with social, environmental and economic factors. The procedure was developed in a GIS environment for Belize and Nigeria. Areas within the charts were prioritized based on zone of confidence, source diagrams, chart quality symbols/indicators, doubtful danger markings, survey completeness, navigationally-significant depths, and areas of significant maritime importance

Future directions in hydrography using satellite-derived bathymetry

Satellite remote sensing provides useful reconnaissance tool for mapping near-shore bathymetry, characterizing a coastal area and monitoring any seafloor changes that may have occurred since the last hydrographic survey of the area. At the 2012 Canada Hydro conference, a study was presented on the potential use of Landsat satellite imagery to map shallow-water bathymetry in a GIS environment over three study sites. Since then, several collaborations between the current study group and various hydrographic organizations were established with the goal of implementing optically-derived bathymetry as part of their data acquiring procedure. Bathymetry over additional study sites around the world was tested. Also, different commercial software packages were evaluated to provide an affordable processing platform for hydrographic offices in developing countries. In this paper, an overview will be provided on the advances that have been achieved in the past year and an update and future directions of the study

Development of a Geo-spatial Analysis Methodology for Assessing the Adequacy of Hydrographic Surveys and Nautical Charts

IHO Publication C-55 (Status of Hydrographic Surveying and Nautical Charting Worldwide) contains information about the progress of hydrographic surveying and nautical charting for a country with navigable waters under its jurisdiction. Listed primarily as percent coverage, it is difficult to use this information to determine: 1) if the current level of surveying or charting is adequate or in need of action, or 2) can be used to compare different locations. An analysis and assessment methodology has been developed to assess the adequacy of hydrographic surveying and nautical charting coverage. Indications of chart adequacy and completeness as depicted on current charts or sailing directions are spatially correlated with significant maritime sites/areas associated with social, environmental and economic factors. Areas within the charts were prioritized low, medium and high priority areas for survey. However, analysis based solely on these datasets is limited to data available at the time of last survey. Publically-available, multi-spectral satellite imagery and published algorithms can be used to derive estimates of the relative bathymetry in shallow, clear waters. The potential of this method was evaluated in terms of supplementing the priority procedure in assessing the adequacy hydrographic surveying and nautical charting coverage. Preliminary results show that multi-spectral satellite remote sensing can be a beneficial reconnaissance tool prior to conducting a hydrographic acoustic survey and for marine spatial planning. Both procedures were developed in a GIS environment for Belize and Nigeria. Presenter Bio Chukwuma Azuike is a hydrographer with the Nigerian Hydrographic Office. A 2000 graduate of the Nigerian Defense Academy, he has served in a variety of naval positions in the Nigerian Navy. In 2010, he began a MS Degree program at the Center for Coastal and Ocean Mapping at the University of New Hampshire

Development of a Geo-spatial Analysis Methodology for Assessing the Adequacy of Hydrographic Surveys and Nautical Charts

IHO Publication C-55 (Status of Hydrographic Surveying and Nautical Charting Worldwide) contains information about the progress of hydrographic surveying and nautical charting for a country with navigable waters under its jurisdiction. Listed primarily as percent coverage, it is difficult to use this information to determine: 1) if the current level of surveying or charting is adequate or in need of action, or 2) can be used to compare different locations. An analysis and assessment methodology has been developed to assess the adequacy of hydrographic surveying and nautical charting coverage. Indications of chart adequacy and completeness as depicted on current charts or sailing directions are spatially correlated with significant maritime sites/areas associated with social, environmental and economic factors. Areas within the charts were prioritized low, medium and high priority areas for survey. However, analysis based solely on these datasets is limited to data available at the time of last survey. Publically-available, multi-spectral satellite imagery and published algorithms can be used to derive estimates of the relative bathymetry in shallow, clear waters. The potential of this method was evaluated in terms of supplementing the priority procedure in assessing the adequacy hydrographic surveying and nautical charting coverage. Preliminary results show that multi-spectral satellite remote sensing can be a beneficial reconnaissance tool prior to conducting a hydrographic acoustic survey and for marine spatial planning. Both procedures were developed in a GIS environment for Belize and Nigeria. Presenter Bio Chukwuma Azuike is a hydrographer with the Nigerian Hydrographic Office. A 2000 graduate of the Nigerian Defense Academy, he has served in a variety of naval positions in the Nigerian Navy. In 2010, he began a MS Degree program at the Center for Coastal and Ocean Mapping at the University of New Hampshire

Satellite Remote Sensing as a Reconnaissance Tool for Assessing Nautical Chart Adequacy and Completeness

National hydrographic offices need a better means of assessing the adequacy of existing nautical charts in order to plan and prioritize future hydrographic surveys. The ability to derive bathymetry from multispectral satellite imagery is a topic that has received considerable attention in scientific literature. However, published studies have not addressed the ability of satellite-derived bathymetry to meet specific hydrographic survey requirements. Specifically, the bathymetry needs to be referenced to a chart datum and statistical uncertainty estimates of the bathymetry should be provided. Ideally, the procedure should be based on readily-available, low-cost software, tools, and data. This paper describes the development and testing of a procedure using publicly-available, multispectral satellite imagery to map and portray shallow-water bathymetry in a GIS environment for three study sites: Northeast United States, Nigeria, and Belize. Landsat imagery and published algorithms were used to derive estimates of the bathymetry in shallow waters, and uncertainty of the satellite-derived bathymetry was then assessed using a Monte Carlo method. Results indicate that the practical procedures developed in this study are suitable for use by national hydrographic offices