SMS:CMS-Wave Wave Output File

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CMS-Wave creates a solution consisting of wave heights, periods and directions at each cell in the domain. These values are stored in a single file for all input spectra. This file is the "wav" file. In SMS terminology, theses are scalar datasets on the grid.

When SMS reads the values from this file, it creates scalar datasets for height and period, and a vector data set to represent the direction. The direction is stored as a rotation from the I direction of the grid. SMS converts this to a (x,y) vector and scales it by the wave height at the cell. The user of SMS should be aware that the wave direction values displayed in the interface are computed by scaling and rotating from those stored in the "wav" solution file.

The WAV file created by CMS-Wave is an ASCII data file. There is no header or identifier as to what the data in the file is, other than the default extension of "*.wav". However, that is not even required.

The first line of the file contains the dimensions of the grid (number of columns, number of rows) and the default size of a grid cell (in the I direction and then the J direction). If the grid does not consist of cells of constant size, the size for the J direction will be written as 999. Since this file is only utilized for dataset values, the dimensions are not important here.

The second line of the file contains the index of the case or wave spectra that resulted in these solution values. This is typically either a coded date (YYMMDDHH or YYYYMMDDHHMM), a simple index (1, 2, 3, ...) or a bin number indicating principal direction and period.

The values in the file are organized in row major format, starting with the "top" row (farthest away from the grid origin) and ending with the "bottom" row (closest to the origin and following the I direction). The values for wave height are output first, followed by a block of values for period, followed by a block of values for direction.

CMS-Wave writes files with up to 16 values per row.

Sample File

80 80 10.000 10.000 // number of columns, number of rows, cell dimensions (dimensions are ignored)
201305281500 // index of first case in the simulation - often a coded date
1.000 1.000 1.000 1.000 ... 1.004 // first n wave heights of cells on the top row (can reflect wave growth due to wind)
1.146 1.151 1.153 1.151 ... 1.128 // next n wave heights
. . . // remaining wave height values
7.7 7.7 7.7 7.7 7.7 ... 7.7 // first n wave periods of cells on the top row
7.7 7.7 7.7 7.7 4.3 ... 4.3 // next n wave periods
. . . // remaining wave period values
-9.9 -9.8 -9.7 -9.6 ... -9.4 // first n wave directions (rotation from the I direction) at cells on the top row
. . . // remaining directions
201305281800 // index of next case in the simulation
. . . // data for this case, repeated for each case

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