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Preparation and sampling of depth data - Demonstration Case

Use of the TRIGRID package is illustrated here by an application to the waters around James Island in Haro Strait, in the inland marine waters between British Columbia, Canada, and Washington State, USA (see Figure 2.1). Detailed instructions are given on use of the programs required at each stage and figures at the end of the chapter show various interim stages in the process of preparing a depth grid for this area.

Figure: This figure shows the coastlines and bathymetry of the area for which an irregular triangular grid is to be constructed. Features to note are the relatively deep channels running north-south on both sides of the island and the very shallow water just south of the island.

Digitising tables and their support software vary too much from make to make and from installation to installation for it to be feasible to include digitising software in the TRIGRID package. It is left to the user to acquire, by one means or another, digitised coastline, contour and soundings files for the area under study, in the formats required by TRIGRID, as specified in Part III. This demonstration case therefore starts at a point where coastline and bathymetric data are available in formats suitable for input to the first TRIGRID program, the SAMPLER.

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