Towards a Federated Marine SDI: Connecting Land and Sea to Protect the Arctic Environment Engineering Report

An Application Programming Interface (API) is a standard set of documented and supported functions and procedures that expose the capabilities or data of an operating system, application, or service to other applications [adapted from ISO/IEC TR 13066-2:2016].

DDIL (Denied, Disrupted, Intermittent, and Limited Bandwidth environments) to describe scenarios where the connectivity is not ideal and actions need to be taken to guarantee a normal or minimum operation of software applications.

Interoperability is the ability to communicate, execute programs, or transfer data among various functional units in a manner that requires the user to have little or no knowledge of the unique characteristics of those units

MSDI is a specific type of Spatial Data Infrastructure (SDI) with a focus on the marine environment.

The FMSDI pilot built on the works of prior initiatives, such as the Marine Spatial Data Infrastructure Concept Development Study, the Maritime Limits and Boundaries Pilot, and the Arctic Spatial Data Infrastructure Pilot. Currently, FMSDI initiative include the following three phases which will be extended in future.

The IHO is a high level domain specific international intergovernmental standards organization, often represented by their national hydrographic offices. The IHO initially developed unique stand-alone standards, such as the IHO Transfer Standard for Digital Hydrographic Data S-57, but is in the process of replacing these standards with standards based on the ISO Geographic information/Geomatics standards (i.e., ISO/TC 211). The transition to the new IHO Universal Hydrographic Data Model (S-100) is in progress, and much of the hydrographic data currently in use is built to S-57 and is therefore only partially suitable for use with many of the Web Services standards and APIs available from OGC.

IHO S-100, the framework standard, has been under development since the publication of its predecessor, IHO S-57 in 2001. IHO S-57, the current standard for the encoding of Electronic Navigational Charts under the SOLAS convention is a vector based standard developed specifically for the purpose of encoding charts for the purpose of safe navigation but S-100, conceived shortly afterwards represented a much bigger step forward.

S-100 aimed to overcome many of the perceived shortcomings of the newly released S-57 standard and was defined as a much broader standard where a framework of ISO-like structures was defined leaving the details of content and encoding to the authors of specific product specifications which would then sit alongside the main framework. S-100 therefore had the following goals:

S-100 is currently at edition 4.0.0 with edition 5.0.0 in preparation. As part of the development of S-100 two encodings for vector feature data were defined, one was ISO8211, a compact binary format used predominantly in the encoding of Vector ENC charts, and the other was the S-100 GML profile, Part 10b. The S-100 GML (Geography Markup Language) profile is a subset of GML ISO19136 designed to support the encoding of simple vector datasets. The S-100 GML profile was developed by the UK around 2013 and incorporated into S-100 as Part 10b shortly thereafter. The profile has been used by various project teams within the IHOs Nautical Publications working group as well as other S-100 based product specification developments. S-100 does not define data content but only provides a toolkit for its definition. Data content is defined within S-100 product specifications. These product specifications detail how data is defined, aggregated, and exchanged along with metadata such as coverage, CRS, geometry and encoding details. The detailed definitions of feature, attribute and associations for an individual product specification are contained within its feature catalog and also lodged in the IHOs geospatial registry; an ISO compliant registry where all S-100 products' definitions, concepts and details are kept and reconciled by a dedicated team.

The following S-100 product specifications were used during this pilot:

It is important to note, then, that the development of IHO S-100 has continued during the Pilot’s progress and this is reflected in updates to the existing S-100 standard. This Pilot remains the most up to date implementation of the S-100 framework to date and certainly one of the few with concrete reference implementations in software from multiple participating vendors.

OGC’s main interaction with the marine community is mainly through its established Marine Domain Working Group (MDWG), formed within the IHO/OGC memorandum of understanding (MOU). This group was formed to address the gaps in the OGC framework within the marine domain. For many years the IHO has run an MSDI community through its MSDIWG and the OGC MDWG works closely with the MSDIWG to cross-fertilize ideas and outline where opportunities exist to improve the ecosystem for the benefit of stakeholders.

The OGC MDWG has a focus on the S-100 framework and its broader integration into the OGC community. This process is likely to take some time and the MLB Pilot is a significant step in exploring such interfaces. IHO and OGC standards have many common elements and both derive largely from overarching ISO standards. The practicalities of their use alongside each other are not always well defined however and the project has sought to explore these practical steps as much as possible.

For several years, the OGC members have worked on developing a family of Web API standards for the various geospatial resource types. These APIs are defined using OpenAPI. As the OGC API standards keep evolving, are approved by the OGC and are implemented by the community, the aviation industry can subsequently experiment and implement them.

The following OGC API Standards and Draft Specifications were used for the development of APIs during this Pilot.

OGC API – Features: a multi-part standard that defines the capability to create, modify, and query vector feature data on the Web and specifies requirements and recommendations for APIs that want to follow a standard way of accessing and sharing feature data. It currently consists of the following four parts.

OGC API - Maps: Maps offers a modern approach to the OGC Web Map Service (WMS) standard for provision map and raster content.

OGC API – Common: Common provides those elements shared by most or all of the OGC API standards to ensure consistency across the family.

OGC API - Processes: Processes allow for processing tools to be called and combined from many sources and applied to data in other OGC API resources though a simple API.

OGC API - EDR: The Environmental Data Retrieval (EDR) Application Programming Interface (API) provides a family of lightweight query interfaces to access spatio-temporal data resources by requesting data at a Position, within an Area, along a Trajectory or through a Corridor. A spatio-temporal data resource is a collection of spatio-temporal data that can be sampled using the EDR query pattern geometries. These patterns are described in the section describing the Core Requirements Class.

OGC API – Tiles: This API defines how to discover which resources offered by the Web API can be retrieved as tiles, retrieve metadata about the tile set (including the supported tile matrix sets, the limits of the tiled set inside the tile matrix set) and how to request a tile.

OGC SensorThings API: Provides an open, geospatial-enabled and unified way to interconnect the Internet of Things (IoT) devices, data, and applications over the Web.

Draft OGC API - DGGS: This draft API enables applications to organize and access data arranged according to a Discrete Global Grid System (DGGS).

Draft OGC API Coverages: Coverages allows discovery, visualization and query of complex raster stacks and data cubes.

Draft OGC API – Styles: This draft API specifies building blocks for OGC Web APIs that enables map servers and clients as well as visual style editors to manage and fetch styles.

The development and adoption of these APIs is likely to have a significant impact on how organizations like IHO engineer systems which seek to be interoperable within OGC standards. The move to an API based interconnecting system of standards clarifies the dividing line between content, its expression within a technical encapsulation (its encoding) and the transport of that data to its ultimate destination.

The IHO, similarly, is instigating a major drive towards implementation of IHO S-100. The standard, many years in the making, is already key to many activities and initiatives in the marine domain. Of particular note is the IMO’s eNavigation initiative, for which S-100 forms the common maritime data structure (CMDS). The IHO is embarking on a push to get S-100 accepted as equivalent for carriage of charts and publications under the global SOLAS convention, a large undertaking and one which will embed its use in live vessel navigation for many years. As a dynamic standard which relies on the creation of product specifications S-100 is wholly dependent on its ability to be interoperable with other standards frameworks and to remain current with those frameworks.

This project is intended to contribute positively to both the OGCs APIs interface with the IHO and to assist the productionisation of S-100 as part of the implementation roadmap.

Where possible, participants incorporate the Arctic Regional Marine Spatial Data Infrastructures Working Group’s (ARMSDIWG) Arctic Voyage Planning Guide (AVPG). The AVPG is intended as a strategic planning tool and a compilation of data and services for national and international vessels traveling in the Arctic. This guide is currently in its development stage. An example of a Canadian implementation is shown in Appendix B. Participants attempted to utilize multiple data from the below list of themes and content while identifying gaps, and making recommendations to improve the federation of data services required for usability of voyage planning in the Arctic.

The Arctic Voyage Planning Guide contains the following themes and content.