Marine GIS Data Model:

Background

Data models lie at the very heart of GIS. A data model for marine applications is complex as modern marine datasets are generated by an extremely varied array of instruments and platforms, all with differing formats, resolutions, and sets of attributes.

There are also many different data structures, such as tables of chemical concentration, raster images of sea surface temperature, gridded bathymetry, four-dimensional data, etc. The basic data models available in GIS do not meet the needs of this diverse range of marine objects and their dynamic behaviours.

Over the last five years or so, work has been underway to develop a marine data model to facilitate the representation and analysis of marine features in a GIS. One of the goals of the marine data model is to provide a structures framework that will accurately represent the dynamic nature of the marine environment. The Arc Marine data model defines a common set of marine data types and has been developed to represent the essential elements for a broad range of marine and coastal data types and processes.

Arc Marine - the ArcGIS Marine Data Model

Arc Marine Data Model

The goal is to provide more accurate representations of location and spatial extent, along with a means for conducting more complex spatial analyses of marine and coastal data by capturing the behavior of real-world objects in a geodatabase. The five groups of Arc Marine data types are: Marine Points, Marine Lines, Marine Areas, Time Series & Measurements, and Mesh (u|thumb|Arc Marine Data Modelsed for storing the results of numerical modelling of marine phenomena, particularly finite element modelling). The Arc Marine Website ^[1], has detailed project information, including an Arc Marine tutorial, data model diagrams and supporting documents.

The common marine data types used in Arc Marine extend the standard ArcGIS data structures (points, lines, polygons and raster) to include temporal referenced data structures that allow for better representation of dynamic marine data.

Feature Types

The extended marine feature types include:

• Instantaneous points - snapshot attributes that are only good for that snapshot in time, for example, a whale sighting.
• Time duration points - points fixed in space, recording continuously over time, such as a moored buoy.
• Time series points - fixed points that track as a time series
• Time duration vector - such as a cruise track that has a start and stop time
• Time duration area - areas that persist temporarily, such as areas where fishing is allowed or not allowed during the certain times of the year

Arc Marine Goals

The goals of Arc Marine include:

• Production of a common structure, a "geodatabase template," for assembling, managing, and publishing marine data in ArcGIS.
• Extending the power of marine GIS analyses by providing a framework for incorporating behaviours in data, and dealing more effectively with scale dependencies.
• Providing a mechanism for the implementation of data content standards.