Properties Map

Starting in version 2.0, dBSea allows you to define these properties at different map locations: water (salinity, temperature, current), sound speed profile (SSP), seabed (a list of layers, each with speed of sound, density and attenuation). Each set of properties is defined at a given easting and northing.

The solvers interpolate the properties at any given point, via an inverse distance weighting.

The properties map can be edited in the Properties Map form, accessed from the setup tab. Properties can be added, duplicated and removed. The locations for the properties list are shown on the map by coloured circles, the currently active properties are indicated on the map by a ring around the circle.

When on the water or seabed tabs, the currently selected properties can be changed by the dropdown box at the top of the frame.

A JSON import feature is provided, for use where a large number of properties is required (eg where SSPs have been measured at a large number of survey points). The imported file should be plain ascii text, with correctly formatted JSON, as shown in the following example.

[{
   "easting": 1234,
    "northing": 5.678e3,
    "name": "A name",
   "comments": "Some comments",
    "colour": "#ff0000",    
    "water": {
      "temperature": 20,
      "salinity": 35,
     "velocity": 10,
     "direction": 1.2e-01,
       "name": "A name",
       "comments": "Some comments"
 },
  "ssp": {
        "cProfile": {
           "depth": [0, 10, 15, 20, 55],
           "c": [1500, 1510, 1520, 1510, 1500]
     },
      "name": "A name",
       "comments": "Some comments"
 },
  "seabed": {
     "name": "Seabed name",
      "comments": "Seabed comments",
      "isReferencedFromSeafloor": true,
       "layers": [
         {
               "depth": 0,
             "name": "A name",
               "comments": "Some comments",
                "material": {
                   "c": 1700,
                  "density": 1500,
                    "attenuation": 0.1,
                 "name": "A name",
                   "comments": "Some comments"
             }
           },{
             "depth": 10,
                "name": "A name",
               "comments": "Some comments",
                "material": {
                   "c": 1820,
                  "density": 1810,
                    "attenuation": 0.05,
                    "name": "A name",
                   "comments": "Some comments"
             }
           }
       ]
   }
},
{
    "easting": 12342,
   "northing": 56782,
  "name": "A name2",
  "comments": "Some comments2",
   "colour": "#00ff00",    
    "water": {
      "temperature": 5,
       "salinity": 3,
      "velocity": 2.7,
        "direction": 0.2,
       "name": "A name",
       "comments": "Some comments"
 },
  "ssp": {
        "cProfile": {
           "depth": [0, 10],
           "c": [1500, 1530]
       },
      "name": "A name",
       "comments": "Some comments"
 },
  "seabed": {
     "name": "Seabed name 2",
        "comments": "Seabed comments 2",
        "isReferencedFromSeafloor": true,
       "layers": [
         {
               "depth": 0,
             "name": "A name",
               "comments": "Some comments",
                "material": {
                   "c": 2510,
                  "density": 2000,
                    "attenuation": 0.1,
                 "name": "A name",
                   "comments": "Some comments"
             }
           },{
             "depth": 20,
                "name": "A name",
               "comments": "Some comments",
                "material": {
                   "c": 2400,
                  "density": 2500,
                    "attenuation": 0.05,
                    "name": "A name",
                   "comments": "Some comments"
             }
           }
       ]
   }
}]

Using the above as a template is recommended to ensure the correct fields are included.

Notes:

Name, comments, and colour fields are optional. Other fields are mandatory.
Colour fields accept HTML-style colour codes, including the # symbol eg #00ff00.
Numerical fields may be entered as 1234.567, 1.234e3, 2.3e-03, and other variations on scientific notation. Not-a-number (NaN) is not supported.
The outermost list (between []) may be extended to include any number of entries.
SSPs:
- The number of entries in the depth and c lists for an individual cProfile must match. However, different locations may have differing lists (both list length and entry depths may differ).
- When interpolating SSPs, all input SSPs have entries added as needed (via linear interpolation or nearest neighbour when extrapolating) so that all have the same depth entries. The depths used are the union set of all input SSP depths.
- The speed at each depth in the output SSP is interpolated from the corresponding depth entries in the input SSPs, via inverse distance weighting.
- Example:
  - SSP A: depths: [0, 20, 40], c: [1500, 1510, 1520].
  - SSP B: depths: [0, 30, 60, 80], c: [1550, 1540, 1530, 1520].
  - Output at the midpoint between SSP A and SSP B: depths: [0, 20, 30, 40, 60, 80], c: [1525, 1526.67, 1527.5, 1528.33, 1525, 1520].
Seabeds:
- Density is in \(\mathrm{kg/m^3}\)
- Each entry must have the same number of seabed layers, and the layers must appear in order of increasing depth.
- Layer properties may differ between corresponding layers at different locations. For example, Location 1 layer density = 1500, Location 2 layer density = 1650.
- Layers of 0 thickness are allowed by setting the layer depth the same as the preceding layer.
- If a seabed is referenced from the seafloor, the first layer depth must be 0.
- Seabed layer properties (including depth) are interpolated from the corresponding layers at each defined location. For example, output layer n is interpolated from Location m layer n for all m via inverse distance weighting.