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## Output locations

FRAme 'sname' [xpfr] [ypfr] [alpfr] [xlenfr] [ylenfr] [mxfr] [myfr])


CANNOT BE USED IN 1D-MODE.

With this optional command the user defines output on a rectangular, uniform grid in a regular frame.

If the set of output locations is identical to a part of the computational grid, then the user can use the alternative command GROUP.

 'sname' name of the frame defined by this command [xpfr] x -coordinate of the origin of the frame in problem coordinates if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [ypfr] y -coordinate of the origin of the frame in problem coordinates if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [alpfr] direction of the x -axis of the frame (in degrees, Cartesian convention; must be 0 in case of spherical coordinates) [xlenfr] length of the frame in x -direction if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [ylenfr] length of the frame in y -direction if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [mxfr] number of meshes in x -direction of the rectangular grid in the frame (one less than the number of grid points in this direction) Default: [mxfr]=20 [myfr] number of meshes in y -direction of the rectangular grid in the frame (one less than the number of grid points in this direction) Default: [myfr]=20

Some output may be required on a frame that is identical with the input (bottom/current) grid or with the computational grid (e.g. for test purposes or to avoid interpolation errors in the output). These frames need not be defined by the user with this command FRAME; the frames are always generated automatically by SWAN under the names 'sname' = 'BOTTGRID' (for the bottom/current grid) and 'sname' = 'COMPGRID' (for the computational grid).

GROUP 'sname' SUBGrid [ix1] [ix2] [iy1] [iy2]


CANNOT BE USED IN 1D-MODE AND IN CASE OF UNSTRUCTURED GRIDS.

With this optional command the user defines a group of output locations on a rectangular or curvilinear grid that is identical with (part of) the computational grid (rectilinear or curvilinear). Such a group may be convenient for the user to obtain output that is not affected by interpolation errors (which would occur when an output grid is used that is not identical with (part of) the computational grid).

Command CGRID should precede this command GROUP.

The subgrid contains those points (ix,iy) of the computational grid for which:
[ix1] ix [ix2] and [iy1] iy [iy2]

For convenience the size of the group, the corner coordinates and the angle with the problem coordinate system are written to PRINT file. The origin of the computational grid is (ix=0,iy=0)!

 'sname' name of the set of output locations defined by this command [ix1] lowest grid index of subgrid in terms of computational grid in ix-direction [iy1] lowest grid index of subgrid in terms of computational grid in iy-direction [ix2] highest grid index of subgrid in terms of computational grid in ix-direction [iy2] highest grid index of subgrid in terms of computational grid in iy-direction

Limitations:
[ix1]0, [ix2][mxc], [iy1]0, [iy2][myc] ([mxc] and [myc] as defined in the command CGRID).

CURve 'sname' [xp1] [yp1]  < [int] [xp] [yp] >


With this optional command the user defines output along a curved line. Actually this curve is a broken line, defined by the user with its corner points. The values of the output quantities along the curve are interpolated from the computational grid. This command may be used more than once to define more curves.

In some cases output is required on (part of) the boundary. To make this easier the following output curves are pre-defined (i.e. they do not have to be defined by the user): the curve BOUNDARY which corresponds to the whole outer boundary, and the curves BOUND_01, BOUND_02, etc. corresponding to parts of the boundary. In regular and curvilinear grids these parts are the four sides of the computational grid; in unstructured grids they are defined in the grid definition file. Examples:

• TABLE 'BOUNDARY' HEAD 'boundary.tab' XP YP
• TABLE 'BOUND_02' HEAD 'bnd2.tab' XP YP
The result is a file where the coordinates of the whole boundary and boundary part 2 are printed. This information can be useful when preparing a BOUNDSPEC command for any type of computational grid.

 'sname' name of the curve [xp1],[yp1] problem coordinates of the first point of the curve if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [int] SWAN will generate output at [int]-1 equidistant locations between two subsequent corner points of the curve (including the two corner points of the curve) [xp],[yp] problem coordinates of a corner point of the curve. Repeat the group [int] [xp] [yp] in proper order if there are more corner points on the curve.

RAY 'rname' [xp1] [yp1] [xq1] [yq1]  <  [int] [xp] [yp] [xq] [yq] >


CANNOT BE USED IN 1D-MODE.

With this optional command the user provides SWAN with information to determine output locations along the depth contour line(s) defined subsequently in command ISOLINE (see below).

These locations are determined by SWAN as the intersections of the depth contour line(s) and the set of straight rays defined in this command RAY. These rays are characterized by a set of master rays defined by their start and end positions ([xp],[yp]) and ([xq],[yq]). Between each pair of sequential master rays thus defined SWAN generates [int]-1 intermediate rays by linear interpolation of the start and end positions.

Note that the rays thus defined have nothing in common with wave rays (e.g. as obtained from conventional refraction computations).

Also note that when using rays, the input grid for bottom and water level should not be curvilinear.

 'rname' name of the set of rays defined by this command. [xp1],[yp1], problem coordinates of the begin and end points of the first master ray [xq1],[yq1] if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [int] number of subdivisions between the previous master ray and the following master ray defined by the following data (number of subdivisions is one more than the number of interpolated rays) [xp],[yp], problem coordinates of the begin and end points of each subsequent master ray [xq],[yq] if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD)

                            | -> DEPth   |
ISOline  'sname'  'rname'  <              >  [dep]
|    BOTtom  |


CANNOT BE USED IN 1D-MODE.

With this optional command the user defines a set of output locations along one depth or bottom level contour line (in combination with command RAY).

 'sname' name of the set of output locations defined by this command 'rname' name of the set of rays (as defined in command RAY) [dep] the depth (in m) of the depth contour line along which output locations are generated by SWAN. If the keyword DEPTH is employed, the stationary water depth is used, if the keyword BOTTOM appears, the water level is ignored, i.e. the depth with respect to datum level is used.

The set of output locations along the depth contour lines created with this command is of the type CURVE.

                   |  < [xp] [yp] >  |
POINts   'sname'  <                   >
|  FILE  'fname'  |


With this optional command the user defines a set of individual output locations (points). The coordinates of these points are given in the command itself or read from a file (option FILE).

 'sname' name of the points [xp],[yp] problem coordinates of one output location if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) 'fname' name of the file containing the output locations.

               | [xpn] [ypn] [alpn] [xlenn] [ylenn] [mxn] [myn]
|
NGRid 'sname' <                 | -> TRIAngle |
| UNSTRUCtured  <               > 'fname'
|                |    EASYmesh |


CANNOT BE USED IN 1D-MODE.

If the user wishes to carry out nested SWAN run(s), a separate coarse-grid SWAN run is required. With this optional command NGRID, the user defines in the present coarse-grid run, a set of output locations along the boundary of the subsequent nested computational grid. The set of output locations thus defined is of the type NGRID.

Command NESTOUT is required after this command NGRID to generate some data for the (subsequent) nested run (not with command BLOCK because a set of locations of the type NGRID does represent an outline and not a geographic region).

 'sname' name of the set of output locations along the boundaries of the following nested computational grid defined by this command [xpn] geographic location of the origin of the computational grid of this coarse-grid run in the problem coordinate system (x -coordinate) if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [ypn] geographic location of the origin of the computational grid of this coarse-grid run in the problem coordinate system (y -coordinate) if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [alpn] direction of the positive x -axis of the computational grid of this coarse-grid run (in degrees, Cartesian convention). [xlenn] length in the x -direction of the nested grid if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [ylenn] length in the y -direction of the nested grid if Cartesian coordinates are used in m if spherical coordinates are used in degrees (see command COORD) [mxn] number of meshes of the output grid in the x -direction of this grid (this number is one less than the number of grid points in this direction!). [mxn] does not have to be equal to the number of meshes in the nested computation; SWAN will interpolate the required information. Default: [mxn] is chosen such that the mesh size of the output grid is (roughly) equal to the mesh size of the coarse grid, but at least 1. [myn] number of meshes of the output grid in the y -direction of this grid (this number is one less than the number of grid points in this direction!). [myn] does not have to be equal to the number of meshes in the nested computation; SWAN will interpolate the required information. Default: [myn] is chosen such that the mesh size of the output grid is (roughly) equal to the mesh size of the coarse grid, but at least 1. UNSTRUCTURE with this option the user indicates that the subsequent nested grid is an unstructured one. Only grids generated by Triangle and Easymesh are supported by SWAN. TRIANGLE the necessary grid information is read from two files as produced by Triangle. The .node and .ele files are required. The basename of these files must be indicated with parameter 'fname'. EASYMESH the necessary grid information is read from two files as produced by Easymesh. The .n and .e files are required. The basename of these files must be indicated with parameter 'fname'. 'fname' basename of the required files, i.e. without extension.

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The SWAN team 2017-03-23