The key to modern geospatial solutions for coastal applications
Introduction
A wide range of digital geospatial technologies have long been used in the planning and management of ports, terminals and coastal zones. These technologies are becoming increasingly important as their capabilities increase, as their cost goes down, and as they become integrated via the World Wide Web. Their importance also increases with demands for safer, more efficient ports and terminals and for sustainable development along the world’s coasts.
Interoperability among geospatial technologies and among different technology providers’ products has become a key requirement. In almost any geographic region, and especially in heavily populated regions, people working in different sectors, disciplines, agencies, jurisdictions, and professions have a need for efficient sharing and integration of diverse kinds of information about their region. Fortunately, various standards efforts have made such sharing easier than before.
This article briefly describes geospatial technologies and explains how they are useful in marine and coastal applications, and we look at why it is important that different geospatial systems be able to “talk to” one another.
Diversity of geospatial technologies
The following technologies produce, store, process and display information about earth features and phenomena, where the information is usually referenced to an earth coordinate system:
• Geographic Information Systems (GIS) are geospatial
database systems with analytical and display capabilities. Here are just a few GIS applications:
• Given “data layers” for vegetation cover, bathymetry and tidal flow rates, a new data layer can be produced and displayed that shows regions in which mangrove trees are in close proximity to deep tidal channels. (Some GIS tools enable modeling of three dimensional and four dimensional phenomena like tidal flow.)
• Given precise land elevation data, perhaps from Light Detection And Ranging (LIDAR), collected before and after a hurricane, changes in sand dunes and shoreline contours can be displayed.
• Given ship position, ship engine exhaust emission data, and a dispersion model based on data about prevailing winds in a port, a GIS can calculate and display projected ship exhaust emission plumes.
• Given an aerial or satellite image of a harbour, plus a data layer representing channels and reefs, and a dynamic data feed of ship location coordinates, a “live” map of harbour traffic can be displayed. Ships too close to reefs can trigger an alarm.
• A data layer representing population density in a port region can be used with a transportation data layer to estimate the time necessary to evacuate people in the event of a hazardous fume release, tsunami, or threat of a tanker explosion. Phone numbers of residences and businesses in endangered regions can be called simultaneously and automatically to warn citizens.
Many other applications are possible, and the value of GIS is multiplied by the other geospatial technologies described below.
• Earth observation systems produce, store and manipulate digital images of the earth like that shown in Figure 2. The sensors (cameras) might be on satellites or airplanes, and the images might represent visible light, ultraviolet or infrared light, gravity or magnetic readings, elevation acquired through radar or LIDAR. Different earth features and phenomena radiate or reflect light in characteristic “signatures,” that is, different intensities of radiation in different frequency bands. These signatures can be used to derive many kinds of information from the images. Processed images can be used in a GIS. Stereo images can be used with stereophotogrammetry to produce elevation data and three-dimensional images.
