ENC and GIS Hand in Hand for Hydrospatial Revolution
The future of navigation and maritime GIS
I am sure that all of you have used your cellphones once or twice in your life to get directions from one point to another or to go to a certain place in a city or country where you are visiting or on a job, and that is entirely possible because your smartphone is equipped with a GPS and GoogleMaps but have you ever wondered how that data was collected and how it is linked to each other to give you indications and how to get to those places?
The source of all geographic data is digitization, which can be made passively over a paper chart or a georeferenced image whether via satellites or airborne surveys or actively through topographic and hydrographic surveys with active sensors like total stations and echo-sounders linked with sophisticated positioning systems, and the reason why specialized personnel does these kinds of practices is only to give extra pieces of information about the real-world objects and deliver an interactive experience to the user so that he or she can question the data in depth depending on his or her purpose of usage.
ENC data is a special case but not entirely different from what was mentioned earlier.
What is this ENC you’re talking about?
Electronic Navigation Charts (ENCs) consist of digitized feature objects that describe the maritime environment under a set of rules specified by the IHO ( International Hydrographic Organisation) in their documents necessary for safe navigation.
Like we mentioned earlier about using the cellphone GPS to go from one point to another, The ENC makes that possible at sea by compiling all the feature objects of the ENC in the World Geographic System WGS84 that represents the closest mathematical model of the earth and the positioning system used by all the GPSs and GNSS(Global Navigation Sattelite System) around the world but how can we represent and use the data compiled by the cartographers and make it convenient to our purpose?
The IHO regulated this product in compliance with the IMO ( International Maritime Organisation), SOLAS (Safety Of Life at Sea), and IALA (International Association of Marine Aids to Navigation and Lighthouse Authorities) and issued publications to bind the Official producers with a set of rules to compile the data and to represent it on certified ECDIS ( Electronic Chart Display Information System) or ECS ( Electronic Chart System) and we’ll come back on the difference between the two of them.
While the IHO’s Product Specification S57 is the key documents that regulate the technicalities of compiling all the feature objects on the ENC and how they are related to each other whether, by associations or collection, the S52 specification regulates how the data is displayed on an ECDIS or ECS and make it possible to the user to fully interact with its unique content associated with a special geometric architecture called the “spaghetti geometry”.
ENC data can be purchased by official resellers dealing with official H.Os(Hydrographic Offices) like IC-ENC, Jeppesen, UKHO, NOAA, or private agencies that managed to get a production license from the IHO and launched a web ENC portal like the one made by NOAA providing it for free to navigate and download data, making direct selling of single ENC cells or bundles of when it’s used for long-distance navigation like IC-ENC, PRIMAR, and Navionics.
ENCs were indeed created for Navigation at sea via ECDIS or ECS but with the recent evolutions of the GIS (Geographic Information System) industry and the web explosion during these years, their use is not only restricted to navigation but can be used to locate wrecks or sea-banks for example for fishing or a more scientific purpose like interpolating the soundings on a certain area to create a DTM(digital terrain model) and applied with other data to conclude a certain phenomenon.
ENC data can be imported and exported to other formats by almost all the GIS applications to be used furthermore for other purposes than navigation, free GIS applications like QGIS makes it possible to import such data and specify which feature objects to import like the example of the image on the sole condition that the .000 S57 data is not encrypted under the S63 IHO specification for ENC protection. Once the feature objects you want to use are properly imported, you can export them to any format you want like GML ( geographic markup language), or using the Javascript library Leaflet to create interactive free web-maps with your data, proper hosting, and usage of APIs like the Geo platform created with ArcGIS by NOAA.
