## Generation and Modification of Computational Grids

### From BAWiki

Remark: JANET covers many functions related to grid generation and grid modification.

This page gives you a comprehensive overview about all other programs actually used at BAW-DH for the purpose of grid generation and grid modification and with a functionality not covered by JANET.

## Contents

## Complex Workflows

### Renewal of Bathymetry for Finite Difference Grids ([tr2.]topo.bin)

Graphical representation of the complex workflow concerning the renewal of bathymetry for various finite difference grids (filtype topo.bin and tr2.topo.bin). This figure is also available as a PostScript file.

### Conversion between various Grid File Formats

Graphical representation of several existing conversion possiblities beetween different grid-file formats, also available as PostScript file.

## Model-Independent Preprocessing

### Modification and Display of Topographic Data

- SYNGRID: Generation of artificial bearing data (e.g. along circles).
- DATAUS: Selection of topographic data within an area defined by a surrounding polygon. This program is useful for many many topographic data points.

### Boundary Polygon

IGEL2D: Interactive generation of a boundary polygon for a set of (selected) topographic data points.

### Fairway Dredger Grid

TRASSE: Generation of nodal points for a fairway dredger grid. From these nodal points a FE-grid may be generated by means of triangulation.

### Extraction of depth isolines

VOLUMETH: Extraction of depth isolines out of an FE grid (filetype gitter05.dat/bin).

### Conversion of Grid Files

Several types of grid files are currently used at BAW-DH. The following file types are supported:

- FD-grid of type FIDISOR/FIDIRB
- filetype topo.bin.

- FD-grid of type TRIM
- filetype tr2.topo.bin. and tr2.topo.bin.ind.

- FE-grid of type TICAD
- filetype gitter05.dat/bin.

- FE-grid of type SELAFIN
- filetype selafin.

## Graphic Display of Computational Grids

The following programs are currently available to display FE- and FD-grids:

- FDGITTER05: graphic display for filetype topo.bin.
- TRGITTER05: graphic display for filetype tr2.topo.bin.
- RGFGRID (Delft3D): graphic display for filetype delft3d.grd.

## Preprocessing for Finite Difference Models

The numerical models based on finite differences which are mainly used at BAW-DH are the two-dimensional model TRIM-2D as well as the three-dimensional model TRIM-3D. To generate the grid files for both aforementioned models several programs are can be used.

### Generation of a Computational Grid

- gridfile of type FIDISOR/FIDIRB:

- FD2BASIS: generation of a basic FD-grid (filetype topo.bin) with correct land/water distribution from digitized boundary structures
- TC2GEOM: generation of a FD-grid (filetype topo.bin) from a digital terrain model, which is based on a FE-grid (filetype gitter05.dat/bin).
- TR2FIDI: generation of a FD-grid (filetype topo.bin) from an existing FD-grid (filetype tr2.topo.bin).

- gridfile of type TRIM:

- FD2TRIM: generation of a FD-grid (filetype tr2.topo.bin) from an existing FD-grid (filetype tr2.topo.bin).
- TR2GEOM: generation of a FD-grid (filetype tr2.topo.bin) from a digital terrain model, which is based on a FE-grid (filetype gitter05.dat/bin)

### Manipulation of Computational Grids

- gridfile of type FIDISOR/FIDIRB:

- FD2CUT: Cutting a (small area) partial grid out of a complete grid.
- FD2DEL: Calculating differences of bathymetry by comparing two existing bathymetries stored on two different FD-grids or, alternatively, modification of an existing bathymetry with earlier calculated differences of bathymetry.
- FD2DTOP: Conversion for differences of bathymetry (generated by the program FD2DEL) into a FD-gridfile (filetype topo.bin).
- FD2KACHEL: Cutting a small part of a grid from a complete gridfile, also in combination with numerically calculated results.
- FD2MOD: Generation of modified differences of bathymetry out of regular differences of bathymetry which have been generated by the program FD2DEL before.
- FDGLUE: Glue together two originally different grids to form one large new grid.
- TOP2IN1: Insertion of a small grid into a large grid.

- gridfile of type TRIM:

- TR2KACHEL: Cutting a small part of a grid from a complete gridfile, also in combination with numerically calculated results.

### Modification of Bathymetry

- gridfile of type FIDISOR/FIDIRB:

- FD2ADDTOPO: Update a FIDISOR/FIDIRB topography with data from echo soundings under constraints of digitized structures.
- FD2BAGGER: Deepening of bathymetry (dredging of material).
- FD2REM: Deletion of structures (e.g. groynes, dams) from a FD-grid.
- FD2RIBA: Deepening of bathymetry (dredging of material), but taking into account the effect of dunes or deep areas.
- FD2SPUELER: Reducing bathymetrical depths (disposal of material).
- FD2WEVO: Inversion of the sign (from plus to minus or vice-versa) for the bathymetrical depths.
- GEOMFD2: Generation of a grid out of a set of (representative) topographic data points. The format of the grid file is FIDISOR/FIDIRB (filetype topo.bin).

- gridfile of type TRIM:

- TR2REFRESH: Modify (refresh) bathymetry of a FD-grid with bathymetry given as a digital terrain model defined on an FE-grid (filetype gitter05.dat/bin). Different special actions are available to modify bathymetry, e.g. dredging or disposal of material.

### Calculation of Volumes and Areas

- gridfile of type FIDISOR/FIDIRB:

- FD2HYPSO: Determination of the frequency distribution for bathymetrical depth of a FD-grid.
- FD2DREV: Determination of dredged volumes.

## Preprocessing for Finite Element Models

TELEMAC-2D is based on the finite element method and used at BAW-DH.

### Generation of a Computational Grid

- gridfile of type TICAD (gitter05.dat/bin):

- GRIDCONVERT: Conversion from an existing grid file (filetype selafin).
- JANET: Generation of an FE-grid out of point or polygon data or conversion from an existing grid file (filetypes [[SELAFIN|selafin], untrim_grid.dat and tr2.topo.bin are possible).
- FD2GEOM: Generation of an FE-grid from an existing FIDISOR/FIDIRB grid (filetype topo.bin).
- TR2GEOM: Generation of an FE-grid from an existing TRIM grid (filetype tr2.topo.bin).

- gridfile of type SELAFIN (selafin):

- JANET: Generation of an FE-grid out of point or polygon data or conversion from an existing grid file (filetypes gitter05.dat/bin, untrim_grid.dat and tr2.topo.bin are possible).

### Manipulation of Computational Grids

- gridfile of type TICAD:

### Modification of Bathymetry

- gridfile of type TICAD:

### Calculation of Volumes and Areas

- gridfile of Type TICAD:

## Preprocessing for unstructured orthogonal grid Models

At BAW-DH we use an unstructured orthogonal grid method: UNTRIM. The grid generator JANET is fitted to the needs of this method. It is therefor no surprise that many grid functions useful for this method are integrated in JANET.

### Generation of Grids (filetype untrim_grid.dat)

- GRIDCONVERT: Conversion from an existing grid file (filetypes delft3d.grd, gitter05.dat/bin or selafin are possible).
- JANET: Generation of an UNTRIM-grid out of point or polygon data or conversion from an existing grid file (filetypes gitter05.dat/bin, selafin or tr2.topo.bin are possible).
- TOUTR: Conversion from an existing grid file (filetypes tr2.topo.bin or gitter05.dat/bin).

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