Web-based nautical charts automated compilation from open hydrospatial data

Abstract

Electronic navigational charts (ENCs) are specialised geospatial datasets, issued by or on the authority of a government or hydrographic office, in accordance with the International Hydrographic Organisation's (IHO) standards, specifications and symbol sets. The datasets generally comprise encoded information collected from hydrographic surveys, aimed primarily at the safety of navigation. Most ENCs are not openly available, since the encrypted datasets can be acquired through various license schemes via a centralised distribution network coordinated by two organisations operating on behalf of the coastal states that produce them. This paper describes a methodology and an integrated system developed at the National Technical University of Athens Cartography Laboratory for the generation of web-based nautical charts utilising open data and free software. The system compiles nautical charts compliant with IHO's S-101 latest standard; using open hydrospatial data retrieved from marine spatial data infrastructures (MSDI) and other qualified volunteered geographic information (VGI) sources. Open-source geospatial libraries and web-map vector technologies are used to build the system components and software scripts developed to enable automated compilation. The study also discusses how the system can be improved further by leveraging web services for end-to-end process automation and satellite-derived bathymetry for accurate depiction of seabed topography in low-depth areas.

Increasing Efficiency of Nautical Chart Production and Accessibility to Marine Environment Data through an Open-Science Compilation Workflow

“…This includes their draw order and style, i.e., colors and symbols (see the examples in Figure 4), along with their labels. The portrayal conditional symbology rules as well as the visualization order, minimum and maximum display scales are based on S-4 [77], S-52 [4], and S-101 [94] IHO standards, following the work by Contarinis et al [45].…”

“…This section presents the results as an ENC-like (VNM) product at 1:15,000 compilation scale, following the IHO portrayal rules and using the methods described in Contarinis et al [45]. An overview of the two areas is illustrated in Figure 14 (Thunder Bay at 1:80,000 viewing scale) and Figure 15 (Ottawa River at 1:40,000 viewing scale).…”

“…MSDIs realization is driven by the IHO's S-100 data model for marine domain interoperability, the Open Geopatial Consortium (OGC) APIs, and the World Wide Web Consortium's (W3C) best practices for spatial data publishing on the Web. The services provided through a MSDI can be used for safe and efficient operation of maritime traffic, exploration and exploitation of marine resources, marine spatial planning (MSP), integrated coastal zone management (ICZM), enforcing environmental protection regulations, and charting maritime security information [43][44][45][46].…”

“…With the aim to contribute to the efforts for expanding the holistic automated generalization approaches to the maritime domain, reduce the compilation time of fundamental chart features (land areas, depth areas and contours, soundings, buildings) and develop ENC-like products for applications beyond nautical charting, this work reviews available data sources and investigates the integration, testing, and improvement of existing generalization approaches. The work builds upon the professional experience of authors with nautical charting workflows and their research efforts to automate data collection [47] and individual data generalization tasks [15,32], to validate chart data requirements [6,35,[48][49][50][51][52], to model the nautical chart compilation workflow and generalize ENC Skin-of-the-Earth features with no topological errors [34], to shed light and gain knowledge on the capabilities of free and open software for use in ocean mapping workflows [53,54], to build innovative chart symbology [8,46,[55][56][57][58] and custom chart web services [45].…”