Introduction
Bathymetry is the ocean's depth, often relative to mean sea level, and for every numerical study an important aspect. However, bathymetric data is not often easy to acquire and combine due to differences in vertical and horizontal coordinate systems. The 'Bathymetry' toolbox allows for easy importing, exporting and merging of bathymetric data from a number of on-line and open source datasets. The bathymetric data is available with different resolutions according to different zoom levels (so-called tiles) indicated in brackets in the column resolution.
Usage of the toolbox for exporting
The 'Export' tab in the Working Space allows the user to export data within a predefined Polygon. A Polygon can be made by using the key “Draw Polygon”, which enables the user to draw a polygon with the mouse (left click to draw the polygon, right click or double click to close it). An example can be found in the Figure below.
- “Delete Polygon” is used to delete the polygon.
- “Load Polygon” allows loading an existing polygon file in ASCII format (*.pol).
- “Save Polygon” allows saving the polygon file in ASCII format (*.pol).
Figure: Exporting bathymetric datasets is easily to carry out with Delft Dashboard as can be seen in this example where we export GEBCO '08 data of Ponta Delgada, Portugal.
Usage of the toolbox for importing
- Select file. By selecting the file, Delft Dashboard determines how many cells are needed.
- If you use Matlab or NetCDF as input: make sure the bathymetry information is saved within the variables x, y and z. (lower case)
- Edit settings. Define, for example, the coordainte system, the filename and attributes.
- Generate Tiles. The bathymetry set will be created for Delft Dashboard using tiles.
Figure: Importing other bathymetric datasets is easy to carry out with Delft Dashboard as can be seen in this example where we import LiDAR data of Barnegat Bay, NJ
Available data sets
The available data sets are given in the table below
| Category | Available Databases | Coverage | Resolution (approx.) | Source |
|---|---|---|---|---|
| Other | GEBCO '08 | Global topography | 926 m (1) / 29.630 m (6) | |
| Other | SRTM 4.1 | Global topography | 93 m (1) / 47.407 m (10) | |
| USGS | Hawaii | Bathymetry | 55 m (1) / 872 m (5) | USGS (Curt Storlazzi) |
| USGS | San Francisco Bay | Bathymetry | 100 m (1) / xxx m (5) | USGS website |
| USGS | Southern California | Topography near Los Angeles | 3 m (1) / 384 m (8) | USGS publication |
| NGDC | Coastal Relief Model (CRM) | Bathymetry of the USA | 93 m (1) / 11.852 m (8) | |
| NGDC | ETOPO 1 | Global topography | 1852 m (1) / 118518 m (7) | NOAA website |
| NGDC | ETOPO 2 | Global topography | 3704 m (1) / 118518 m (6) | NOAA website |
| Rijkswaterstaat | Vaklodingen | Bathymetry - the Netherlands | 20 m (1) / 320 m (5) | |
| SURA | Gulf of Mexico | Bathymetry | 93 m (1) / 1481 m (5) | |
| EMODNET | Central Mediterranean | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| EMODNET | Aegean Sea | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| EMODNET | Bay of Biscay | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| EMODNET | Celtic Seas | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| EMODNET | Great North Sea | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| EMODNET | Western Mediterranean | Bathymetry | 463 m (1) / 3704 m (4) | EMODNET webite |
| Marine Scotland | West of Lewis | Topography | 5 m (1) / 80 m (5) | ? |
| Geoscience Australia | Australia | Topography | 278 m (1) / 17778 m (7) | Geoscience Australia |
| NCTR | Southwest Washington | Topography | 45 m (1) / 9744 m (2) | ? |
| DMU | ACE-2 | Altimetry | 93 m (1) / 47407 (10) | ? |
