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Bathymetric data quality and autonomous navigation related research projects

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Christos Kastrisios at University of New Hampshire
Christos Kastrisios
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Abstract

A brief presentation of data quality and autonomous ship navigation related projects at the Center for Coastal and Ocean Mapping, University of New Hampshire.
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➢Constraints
❖Morphology
❖Legibility
❖Topology
❖Safety
“The expected depth must
not appear deeper than
the source information”.
3
“Triangle test”
“No actual sounding
exists within a triangle of
selected soundings which
is less than the least of
any of the soundings
forming the triangle“
“Edge test”
“No actual sounding exists
between two adjacent
selected soundings forming
an edge of the triangle which
is less than the lesser of the
two selected soundings “
30
10
20
19
9
4
5
Intrinsic Limitation
Surface Test
Vertical uncertainty
6
Validation Toolbox
Depth area
appears deeper
5
8
5
Depth area
appears shallower
9
➢Sabre Zenith
▪Length: 40.5 m
▪Draft: 1.5 m
0
10
ECDIS Alarm
11
ENC
Error Inspection Error Remediation
(attribute fixes 1)
Attribute fixes 2
Geometry fixes
Areas of Dominance
Goal
➢Development of comprehensive algorithm that
✓Respects cartographic rules
✓Terrain characteristics
✓Complementary to existing chart features
➢Two-fold project:
✓Hydrographic Sounding Selection
✓Cartographic Sounding Selection Prime
Supportive
Background
DToN
13
“Digital Smooth Sheet”
Source
Soundings
Human
Factors
S-52
Chart
Scale
14
Hydrographic
Sounding Selection
Phase Surface Critical
Points Extraction
Phase
Sounding Selection
Enrichment Phase
SOUACC &
CATZOC
15
➢CLUTTER
➢Obscure high-quality more than low-quality data
➢Not intuitive
➢May not fit in small areas
➢Continuous zoom-in/out is required
➢Dominate the screen
17
ECDIS Day Blackback Mode
➢CLUTTER
➢Obscure high-quality more than low-quality data
➢Not intuitive
➢May not fit in small areas
➢Continuous zoom-in/out is required
➢Dominate the screen
18
--
➢Requirements:
❑Minimize the occlusion of navigational
information.
❑Increase visual weight with the increase
of data uncertainty.
❑Unambiguously visualize the different
uncertainty levels.
❑Be easy to memorize
❑Maintain effectiveness in all ECDIS
modes
19
Benefits:
✓Minimally used
✓Minimally interfere with chart information
✓The combination can be intuitive
✓Good visual hierarchy
Proposed Solution:
Sequence of textures,
created by combining two or more visual variables
20
5 Coding Schemes :
▪Line textures
▪Dot clusters
▪Color lightness and transparency
▪Opaque colors
▪Color stripes
An online survey has been developed for
their evaluation in 4 different areas
Online Survey: https://unh.az1.qualtrics.com/jfe/form/SV_9tPKpnrcZusJ4RT 21
Online Survey: https://unh.az1.qualtrics.com/jfe/form/SV_9tPKpnrcZusJ4RT
4 Areas (3 in day bright, 1 in dusk ECDIS mode)
22
23
➢Individual Features:
➢What?
➢Where?
➢When?
➢How?
➢Factors:
➢Position uncertainty
➢Depth Uncertainty
➢Cartographic uncertainty
Decision Tree
24
•Network of routes and ports from AIS data
•Routes will be classification by max. ship draft
•Route probability
26
AIS
Ports
ENCs
27
28
•Ship Route Suggestion System
•Ship Route Prediction System
•Web Application
30
➢Challenges in OM industry
➢25 professionals from six countries (Brazil, Denmark, France, Greece, Taiwan, and USA)
➢Focus of first phase: data, processing methods, requirements for the deliverables,
verification methods, and deficiencies of the process
-- 31
References
32
1. Kastrisios, C., C. Ware, B.R. Calder, T. Butkiewicz, and L. Alexander. 2020. “Improved Techniques for Depth Quality Information on Navigational Charts.”
Proceedings of the 8th International Conference on Cartography and GIS, vol. 1, Nessebar, Bulgaria, p. 73 –80.
https://www.researchgate.net/publication/341959410_Improved_techniques_for_depth_quality_information_on_navigational_charts
2. Kastrisios, C., B.R. Calder, and M. Bartlett. 2020. “Inspection and Error Remediation of Bathymetric Relationships of Adjoining Geo-Objects in Electronic
Navigational Charts.” Proceedings of the 8th International Conference on Cartography and GIS, vol. 1, 18-23 June 2018, Nessebar, Bulgaria, p. 116 –123.
https://www.researchgate.net/publication/341959139_Inspection_and_error_remediation_of_bathymetric_relationships_of_adjoining_geo-
objects_in_electronic_navigational_charts
3. Cordero J.M., and C. Kastrisios. 2020. “Characterizing free and open-source tools for ocean-mapping.” Proceedings of the 6th Hydrographic Engineering
Conference, Lisbon, Portugal. https://www.researchgate.net/publication/344751310_Characterizing_free_and_open-source_tools_for_ocean-mapping
4. Kastrisios, C., B.R. Calder, G. Masetti, B. Martinez, and P. Holmberg. 2020. “Soundings Validation Toolbox: Research to Operations.” Canadian Hydrographic
Conference, 24-27 February 2020, Quebec City, QC, Canada.
https://www.researchgate.net/publication/340922700_Soundings_Validation_Toolbox_Research_to_Operations
5. Kastrisios, C., B.R. Calder, and M. Bartlett. “ENC Depth Areas: Quality Control of Sea-bottom Surface Continuity and Error Fixes.” 2020. Canadian Hydrographic
Conference, 24-27 February 2020, Quebec City, QC, Canada. https://www.researchgate.net/publication/339525712_ENC_Depth_Areas_Quality_control_of_sea-
bottom_surface_continuity_and_error_fixes
6. Kastrisios, C., C. Ware, B.R. Calder, T. Butkiewicz, and L. Alexander. 2020. “An Alternative Methodology to the Star Symbols.” IHO Data Quality Working Group, 4-7
February 2020, Monaco. https://www.researchgate.net/publication/339080041_An_alternative_methodology_to_the_star_symbols
References
33
7. Kastrisios, C., Ware, C., Calder, B., Butkiewicz, T., Alexander, A. L., & O. Hauser. 2020. “Nautical chart data uncertainty visualization as the means for integrating
bathymetric, meteorological, and oceanographic information in support of coastal navigation.” 100th American Meteorological Society Annual Meeting, 18th
Symposium on the Coastal Environment, Boston, MA. https://www.researchgate.net/publication/337869522_Nautical_chart_data_uncertainty_visualization_
as_the_means_for_integrating_bathymetric_meteorological_and_oceanographic_information_in_support_of_coastal_navigation
8. Kastrisios, C., B.R. Calder, G. Masetti, and P. Holmberg. 2019. “Validation of the shoal-biased pattern of bathymetric information on nautical charts.” Proceedings
of the 29th International Cartographic Conference, 15-19 July 2019, Tokyo, Japan.
https://www.researchgate.net/publication/334504598_Validation_of_the_shoal-biased_pattern_of_bathymetric_information_on_nautical_charts
9. Kastrisios, C., B.R. Calder, G. Masetti, and P. Holmberg. 2019. “Towards Automated Validation of Charted Soundings: Existing Tests and Limitations.” Geo-spatial
Information Science. Taylor & Francis. DOI: 10.1080/10095020.2019.1618636.
https://www.researchgate.net/publication/332292809_Towards_Automated_Validation_of_Charted_Soundings_Existing_Tests_and_Limitations
10. Kastrisios, C., B.R. Calder, G. Masetti, and P. Holmberg. 2019. “On the effective validation of charted soundings and depth curves.” Proceedings of the 2019 US
Hydro Conference, 19-21 March 2019, Biloxi, MS, USA.
https://www.researchgate.net/publication/331470942_On_the_effective_validation_of_charted_soundings_and_depth_curves
11. Masetti, G., T. Faulkes, and C. Kastrisios. 2018. “Automated Identification of Discrepancies Between Nautical Charts and Survey Soundings.” ISPRS International
Journal of Geo-Information, vol. 7. MDPI Publishing, Basel, Switzerland, p. 392, 2018.
https://www.researchgate.net/publication/327939360_Automated_Identification_of_Discrepancies_between_Nautical_Charts_and_Survey_Soundings
12. Kastrisios, C., and B. Calder. 2018. “Algorithmic Implementation of the Triangle Test for the Validation of Charted Soundings.” Proceedings of the 7th International
Conference on Cartography and GIS, 18-23 June 2018, Sozopol, Bulgaria, p. 569 –576. https://www.researchgate.net/publication/325966938_Algorithmic_
implementation_of_the_triangle_test_for_the_validation_of_charted_soundings
ResearchGate has not been able to resolve any citations for this publication.
Characterizing free and open-source tools for ocean-mapping
Conference Paper
Full-text available
  • Oct 2020
Over the last years, scientists and professionals have made available several free and open-source software tools meant for geophysical survey planning, underwater remote sensing data processing, and geospatial data visualization. However, the use of these tools is limited within hydrographic offices. One of the reasons could be the lack of awareness about the functionalities and the performance of the available solutions. The purpose of this paper is to present an overview of free and open-source tools that may be applied to a Hydrographic Office workflow including data acquisition, data processing, quality control, and data visualization.
View
Improved techniques for depth quality information on navigational charts
Conference Paper
Full-text available
  • Jun 2020
Navigational charts contain a combination of geospatial information of varying quality collected at different times using various techniques. Bathymetric data quality is mainly encoded in electronic charts with the Category of Zones of Confidence (CATZOC). CATZOC provides information about the horizontal and vertical uncertainty of depth information, as well as the seabed coverage and feature detection. It is visualized in Electronic Chart Display and Information Systems (ECDIS) as an additional layer with glyphs using a rating system of stars: six to two stars for the best to lowest quality data and "U" for unassessed data. The current symbology creates visual clutter which is worse in areas of high quality bathymetry. Furthermore, horizontal and vertical uncertainties may not be adequately assessed by the user. This paper presents a research program aimed at the development of a method for portraying bathymetric data quality and for integrating the quantified uncertainties in ECDIS.
View
Inspection and error remediation of bathymetric relationships of adjoining geo-objects in electronic navigational charts
Conference Paper
Full-text available
  • Jun 2020
Depth areas are utilized by the Electronic Chart Display and Information Systems (ECDIS) along with the vessel's characteristics (e.g., draft, squat) and other situational information (e.g., tides) for separating safe areas from those unsafe to navigate. Any error in their compilation is carried over to the analysis performed in the ECDIS. As a result, waters may be portrayed deeper, thus posing a risk to the vessel navigating them, or may appear shoaler, thus triggering useless ECDIS alarms which contribute to the situation known as "mariner's deafness". With the exception of crisp boundaries where abrupt changes are expected, the transition between depth areas should be smooth and continuous. In this paper we present a research toward a mechanism for identifying discontinuities and an error remediation approach that proposes changes to the encoded depth range and the geometry of depth areas with identified discontinuities, for the cartographer's attention.
View
ENC Depth Areas. Quality control of sea-bottom surface continuity and error fixes.
Conference Paper
Full-text available
  • Feb 2020
The Electronic Navigational Chart (ENC) consists of point, line, and area features compiled following the node-chain topological model. To ensure that the topological structure is valid, the International Hydrographic Organization (IHO) has developed a number of checks defined in Publication S-58. Many of the checks deal with the vertical component of the nautical chart with the aim to validate consistency among compiled geo-objects. Nevertheless, validation checks are not exhaustive and spatial relationships may be violated. The presented work identifies vertical discontinuities between depth areas and adjoining geo-objects in the ENC and following an iterative approach proposes fixes to the attributes and the geometry of the depth areas with errors.
View
An alternative methodology (to the star symbols).
Presentation
Full-text available
  • Feb 2020
Data quality is visualized in ECDIS as an additional layer with symbols using a rating system of stars: six to two stars for the best to lowest quality data and “U” for unassessed data. This work presents an alternative methodology for consideration by the IHO Data Quality Working Group members.
View
Towards Automated Validation of Charted Soundings: Existing Tests and Limitations
Article
Full-text available
  • Jun 2019
The nautical chart is one of the fundamental tools in navigation used by mariners to plan and safely execute voyages. Its compilation follows strict cartographic constraints with the most prominent being that of the safety. Thereby, the cartographer is called to make the selection of the bathymetric information for portrayal on charts in a way that, at any location, the expected water depth is not deeper than the source information. To validate the shoal-biased pattern of selection two standard tests are used, i.e., the triangle and edge tests. To date, some efforts have been made towards the automation of the triangle test, but the edge test has been largely ignored. In the context of research on a fully automated solution for the compilation of charts at different scales from the source information, this paper presents an algorithmic implementation of the two tests for the validation of selected soundings. Through a case study with real world data it presents the improved performance of the implementation near and within depth curves and coastlines and points out the importance of the edge test in the validation process. It also presents the, by definition, intrinsic limitation of the two tests as part of a fully automated solution and discusses the need for a new test that will complement or supersede the existing ones.
View
On the effective validation of charted soundings and depth curves
Conference Paper
Full-text available
  • Mar 2019
Depth curves and charted soundings are two structural components of nautical charts, both derived from a more detailed dataset through generalization. Once depth curves are generated, the cartographer makes a selection of soundings that complements the depth curves and other features carrying bathymetric information in the adequate representation of the seabed morphology at the scale of the product. The selection of charted soundings – which is currently either performed fully manually, or partially manually using a computer-assisted solution – must meet the safety constraint, i.e., that no source sounding exists that is shoaler than what the mariner would expect by mentally interpolating the charted bathymetric information. According to International Hydrographic Organization S-4 publication, for well-surveyed areas that is achieved through the “triangular method of selection” and consists of two tests: the Triangle Test and the Edge Test. There are currently no fully automated solutions, so, with the ultimate goal of supporting “cartography at point of use”, we consider the problem of automating the validation of shoal-selected soundings. We discuss an implementation of the triangle test with improved performance near linear features, the first automated implementation of the edge test, and that the edge test may identify shoals that the triangle test fails to detect, confirming its significance in the validation process. We demonstrate an “intrinsic” limitation of the two tests that makes infeasible a fully automated solution based solely on the two tests. Finally, to overcome the intrinsic limitation, we propose a new validation test, named Nautical Surface Test, that captures the local morphology at the appropriate charting resolution as the solution for the automated validation of the charted bathymetric information.
View
Automated Identification of Discrepancies between Nautical Charts and Survey Soundings
Article
Full-text available
  • Sep 2018
  • ISPRS
Timely and accurate identification of change detection for areas depicted on nautical charts constitutes a key task for marine cartographic agencies in supporting maritime safety. Such a task is usually achieved through manual or semi-automated processes, based on best practices developed over the years requiring a substantial level of human commitment (i.e., to visually compare the chart with the new collected data or to analyze the result of intermediate products). This work describes an algorithm that aims to largely automate the change identification process as well as to reduce its subjective component. Through the selective derivation of a set of depth points from a nautical chart, a triangulated irregular network is created to apply a preliminary tilted-triangle test to all the input survey soundings. Given the complexity of a modern nautical chart, a set of feature-specific, point-in-polygon tests are then performed. As output, the algorithm provides danger-to-navigation candidates, chart discrepancies, and a subset of features that requires human evaluation. The algorithm has been successfully tested with real-world electronic navigational charts and survey datasets. In parallel to the research development, a prototype application implementing the algorithm was created and made publicly available.
View
Algorithmic implementation of the triangle test for the validation of charted soundings
Conference Paper
Full-text available
  • Jun 2018
The selection of soundings to be shown on nautical charts is one of the most important and complicated tasks in nautical cartography. From the vast number of source soundings the cartographer is called to select all those important for the safety of navigation and to verify the “shoal biased” pattern of selection against the source soundings. A long-term goal of the cartographic community has been the automation of the tasks involved in nautical chart production, including that of the selection and validation of charted soundings. With the aim to contribute to that effort, this paper presents an implementation of the triangle test for the automated validation of selected soundings which has improved performance on the detection of shoals near depth curves and coastlines.
View
Soundings Validation Toolbox: Research to Operations
  • Feb 2020
  • Canadian
  • 24-27
  • C Kastrisios
  • B R Calder
  • G Masetti
  • B Martinez
  • P Holmberg
Kastrisios, C., B.R. Calder, G. Masetti, B. Martinez, and P. Holmberg. 2020. "Soundings Validation Toolbox: Research to Operations." Canadian Hydrographic Conference, 24-27 February 2020, Quebec City, QC, Canada. https://www.researchgate.net/publication/340922700_Soundings_Validation_Toolbox_R