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].

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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.

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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.

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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.

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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:

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

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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:

$z=𝐳𝐳\mathrm{𝟎}+𝐚𝐦𝐩𝐥𝐢𝐭𝐮𝐝𝐞\mathrm{\_}𝐱(1+\sin (f(x)))+𝐬𝐥𝐨𝐩𝐞\mathrm{\_}𝐱(x-𝐱𝐟𝐫𝐨𝐦)+𝐚𝐦𝐩𝐥𝐢𝐭𝐮𝐝𝐞\mathrm{\_}𝐲(1+\sin (f(y)))+𝐬𝐥𝐨𝐩𝐞\mathrm{\_}𝐲(y-𝐲𝐟𝐫𝐨𝐦)$

where:

$f(x)=(x-𝐱𝐟𝐫𝐨𝐦)/(𝐱𝐭𝐨-𝐱𝐟𝐫𝐨𝐦)\ast 2\pi \ast 𝐧𝐮𝐦\mathrm{\_}𝐬𝐰\mathrm{\_}𝐱$

$f(y)=(y-𝐲𝐟𝐫𝐨𝐦)/(𝐲𝐭𝐨-𝐲𝐟𝐫𝐨𝐦)\ast 2\pi \ast 𝐧𝐮𝐦\mathrm{\_}𝐬𝐰\mathrm{\_}𝐲$

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The number of cycles of the sine wave can be a fraction and the sine function rises from a value of $𝐳𝐳\mathrm{𝟎}$ at $(𝐱𝐟𝐫𝐨𝐦,𝐲𝐟𝐫𝐨𝐦)$ as x- and y-values increase. Where the peaks coincide, the maximum elevation is the sum of $𝐳𝐳\mathrm{𝟎}+𝐚𝐦𝐩𝐥𝐢𝐭𝐮𝐝𝐞\mathrm{\_}𝐱+𝐚𝐦𝐩𝐥𝐢𝐭𝐮𝐝𝐞\mathrm{\_}𝐲$.

Elevation from cosine function in xy

As above but uses the cosine function instead of the sine function.

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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.

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