Mesh files

The mesh is specified by three files located in MeshPath.

nod2d.out

The first line states the number of nodes. The following lines define one node each by three, optionally four, entries seperated by one or more spaces

  1. optional: index of this node (Fortran style, counting starts with 1),

  2. longitude [°E] or x-coordinate [m],

  3. latitude [°N] or y-coordinate [m],

  4. node type: Inner node (0), closed boundary (1), open boundary (2), some special treatment (3-…)

    In particular, node type 3 are regarded as nodes exactly on the coastline. When smoothing the topography, the topography at these nodes is kept at 0m.

nodhn.out or set TopoFile in namelist
The bathymetry and topography at each node is usually given in nodhn.out, though this filename may be changed in the namelist to allow for an easy comparison of different geography data sets. Each line contains one value, the water depth [m] at the corresponding node. Notice that negative values mean elevation, thus land nodes.
elem2d.out
The third file elem2d.out defines the elements, i.e., the triangular connection between the nodes. The first line contains the number of elements. The following lines define the elements by stating the three corresponding node indicees in counter clockwise ordering.

Further arrays e.g., for edges, neighbourhood relations, or boundary nodes, are built by TsunAWI on start up.

Here is a small example mesh. See also Examples and small test cases for a link to download test cases ready with namelist and meshes.

../_images/mesh_example.png

which is specified by

nod2d.out elem2d.out nodhn.out
17
1 -2.7 -3.8 1
2 -1.6 -1.7 0
3 -4.7 -1.8 1
4 -4.0  0.4 0
5 -3.3  2.6 1
6 -1.7  3.0 1
7 -1.9  0.9 0
8  0.1  0.0 0
9  1.9  0.9 0
10  0.0  1.8 0
11  0.0  3.5 1
12  1.6  3.0 1
13  3.2  2.5 1
14  4.1  0.2 1
15  1.7 -1.6 0
16  0.7 -4.5 1
17  4.1 -2.9 1
22
1   2   3
1  16   2
2   4   3
2   7   4
2   8   7
2  15   8
2  16  15
4   7   5
5   7   6
6   7  10
6  10  11
7   8  10
8   9  10
8  15   9
8  15   9
9  12  10
9  13  12
9  14  13
9  15  14
10  12  11
14  15  17
15  16  17
18.
12.
20.
8.
0.
-4.
0.
0.
-1.
-2.
-6.
-1.
3.
8.
7.
22.
25.

(Right click on the headers to download the files.)