Electronic charting and digital mapping is becoming very useful in many areas of the earth’s water resources. These include locating shipwrecks, navigating ships and aircraft, engineering surveys, fishing industries, harbours, defence and designing and maintaining pipelines and cables. An image on a computer can provide much more detail and data than on a two-dimensional map or chart. It also allows data to be linked more easily to related data, so that much more detail is available to the user. In the case of an oil pipeline traveling under the ocean, the exact location is available and can be located utilising GPS. The surrounding environment can also be analysed and details of changes can be studied before any maintenance or repair is carried out.
The area of computer technology that handles electronic charting and digital mapping is called a Geographic Information System (GIS). The GIS allows spatial information of all kinds, including charts or maps, topographic mapping called bathymetry, (the study and mapping of seafloor topography), imagery, tracks and updates to be integrated and visualised.
Topographic mapping allows detailed study of natural and artificial features in a particular area. When used under the sea, it can include data about natural features like mountains, reefs and other structures. It also allows layers so that man-made drilling rigs and fish farms can be seen over the basic features. Bathymetry studies the depths of the oceans and gives us an understanding of structures of our earth that were not possible in past ages. We can see images of parts of the oceans as they change and compare them with what has happened previously. It is also possible to study the oceans from many different perspectives using the data collected, viewing underwater features from the top, in profile or from a range of other angles, including three-dimensional imaging. GIS technology is also being used to automate the production of hard copy and digital charts. The use of GIS means updating can be continuous with the latest changes broadcast electronically and available more quickly than in the past. For example, a captain has the ability to print a new chart at the start of a voyage. This chart will be current and up to date at the time of printing. In the past, the chart the Captain may have used could be a number of years old and possibly out of date. This results in greater safety and cost benefits. Whilst it is true that there would very seldom be significant changes to the ocean floor to warrant printing new charts for each voyage, there can be significant events that would require this. For instance, a volcano erupting under the ocean and the changes that this would create. The tsunami of 2004 resulted from a massive earthquake which changed the levels of the ocean and coastline. Then consider how important that information is to the captain of a ship in choosing the safest path to travel to avoid danger to his ship and passengers or cargo.