HydroGeoSphere/Elevation Instructions

These instructions are used to define 3-D mesh base elevations and new layer top elevations.

Elevation constant

 * 1) elev Elevation value [L].
 * &bull; &bull; &bull;

Elevation from gms file

 * 1) basefile Name of the data file containing the elevation values for each node in the 2-D grid. This is a string variable. The file should be formatted as outlined in Section F.2.
 * &bull; &bull; &bull;

Elevation from gb file

 * 1) basefile Name of the data file containing the base elevation values for each node in the 2-D grid. This is a string variable. The file should be formatted as outlined in Section G.2.
 * &bull; &bull; &bull;

Elevation from raster file

 * 1) rasterfile Name of the raster file containing the base elevation values. This is a string variable. The file should be formatted as outlined in Section H.
 * &bull; &bull; &bull;

Elevation from bilinear function in xy

 * 1) xfrom, xto, yfrom, yto x- and y-ranges.
 * 2) a1,a2,a3,a4,a5 Constants for bilinear function.

For nodes falling within the given x- and y-range, the z-coordinate is computed according to the following function:


 * $$z=a1+a2(x-\mathbf{xfrom})+a3(x-\mathbf{xfrom})^2+a4(y-\mathbf{yfrom})+a5(y-\mathbf{yfrom})^2$$


 * &bull; &bull; &bull;

Elevation from sine function in xy

 * 1) xfrom, xto, yfrom, yto x and y ranges.
 * 2) zz0 Elevation at xfrom, yfrom.
 * 3) num_sw_x,amplitude_x,slope_x Number of sine wave cycles, sine wave amplitude and surface slope in the x−direction.
 * 4) num_sw_y,amplitude_y,slope_y As above but in the y−direction.

For nodes falling within the given x- and y-range, the z-coordinate is computed according to the following function:


 * $$z=\mathbf{zz0}+\mathbf{amplitude\_x}(1+\sin (f(x)))+\mathbf{slope\_x}(x-\mathbf{xfrom})+\mathbf{amplitude\_y}(1+\sin (f(y)))+\mathbf{slope\_y}(y-\mathbf{yfrom})$$

where:


 * $$f(x)=(x-\mathbf{xfrom})/(\mathbf{xto}-\mathbf{xfrom})\ast 2{\pi}\ast \mathbf{num\_sw\_x}$$


 * $$f(y)=(y-\mathbf{yfrom})/(\mathbf{yto}-\mathbf{yfrom})\ast 2{\pi}\ast \mathbf{num\_sw\_y}$$


 * &bull; &bull; &bull;

The number of cycles of the sine wave can be a fraction and the sine function rises from a value of $$\mathbf{zz0}$$ at $$(\mathbf{xfrom},\mathbf{yfrom})$$ as x- and y-values increase. Where the peaks coincide, the maximum elevation is the sum of $$\mathbf{zz0}+\mathbf{amplitude\_x}+\mathbf{amplitude\_y}$$.

Elevation from cosine function in xy
As above but uses the cosine function instead of the sine function.
 * &bull; &bull; &bull;

Elevation from xz pairs

 * 1) xval, zval xz-pair 1.
 * 2) xval, zval xz-pair 2.
 * 3) ...etc...
 * 4) xval, zval xz-pair n.
 * 5) end Signals end of list.

Listed xz-coordinate pairs are read until an End instruction is encountered. They should be given in order from smallest to largest x. For each node in the 2-D grid, the x-coordinate of the node is used to determine its position in the list, and a z-coordinate is then interpolated from the neighbouring xz-pairs.
 * &bull; &bull; &bull;