/// <summary>
/// Recursively calculates the nearest sound speed profiles along a given radial using a binary search-like algorithm
/// 1. If start and end points are provided, use them, otherwise find the nearest SSP to each of those points
/// 2. If the start point was calculated, add the SSP closest to the calculated start point to the enumerable
/// 2. If the SSPs closest to the start and end points are within 10m of each other they are considered identical and there are
/// assumed to be no more intervening points
/// 3. If the SSPs closest to the start and end points are NOT within 10m of each other, calculate the midpoint of the segment
/// and find the nearest SSP to that point.
/// 4. If the SSP nearest the midpoint is not within 10m of the SSP nearest to the start point, recursively call this function to
/// find the new midpoint between the start point and the current midpoint
/// 5. Return the
/// </summary>
/// <param name="segment"></param>
/// <param name="startDistance"></param>
/// <param name="startProfile"></param>
/// <param name="endProfile"></param>
/// <param name="bottomProfile"></param>
/// <param name="soundSpeedData"></param>
/// <param name="deepestProfile"></param>
/// <returns></returns>
static IEnumerable<Tuple<double, SoundSpeedProfile>> ProfilesAlongRadial(GeoSegment segment, double startDistance, SoundSpeedProfile startProfile, SoundSpeedProfile endProfile, BottomProfile bottomProfile, EnvironmentData<SoundSpeedProfile> soundSpeedData, SoundSpeedProfile deepestProfile)
{
var returnStartProfile = false;
var returnEndProfile = false;
if (startProfile == null)
{
returnStartProfile = true;
startProfile = soundSpeedData.IsFast2DLookupAvailable
? soundSpeedData.GetNearestPointAsync(segment[0]).Result.Extend(deepestProfile)
: soundSpeedData.GetNearestPoint(segment[0]).Extend(deepestProfile);
}
if (endProfile == null)
{
returnEndProfile = true;
endProfile = soundSpeedData.IsFast2DLookupAvailable
? soundSpeedData.GetNearestPointAsync(segment[1]).Result.Extend(deepestProfile)
: soundSpeedData.GetNearestPoint(segment[1]).Extend(deepestProfile);
}
if (returnStartProfile) yield return Tuple.Create(NearestBottomProfileDistanceTo(bottomProfile, startDistance), startProfile);
// If the start and end profiles are the same, we're done
if (startProfile.DistanceKilometers(endProfile) <= 0.01) yield break;
// If not, create a middle profile
var middleProfile = soundSpeedData.IsFast2DLookupAvailable
? soundSpeedData.GetNearestPointAsync(segment.Center).Result.Extend(deepestProfile)
: soundSpeedData.GetNearestPoint(segment.Center).Extend(deepestProfile);
// If the center profile is different from BOTH endpoints
if (startProfile.DistanceKilometers(middleProfile) > 0.01 && middleProfile.DistanceKilometers(endProfile) > 0.01)
{
// Recursively create and return any new sound speed profiles between the start and the center
var firstHalfSegment = new GeoSegment(segment[0], segment.Center);
foreach (var tuple in ProfilesAlongRadial(firstHalfSegment, startDistance, startProfile, middleProfile, bottomProfile, soundSpeedData, deepestProfile)) yield return tuple;
var centerDistance = startDistance + Geo.RadiansToKilometers(segment[0].DistanceRadians(segment.Center));
// return the center profile
yield return Tuple.Create(NearestBottomProfileDistanceTo(bottomProfile, centerDistance), middleProfile);
// Recursively create and return any new sound speed profiles between the center and the end
var secondHalfSegment = new GeoSegment(segment.Center, segment[1]);
foreach (var tuple in ProfilesAlongRadial(secondHalfSegment, centerDistance, middleProfile, endProfile, bottomProfile, soundSpeedData, deepestProfile)) yield return tuple;
}
var endDistance = startDistance + Geo.RadiansToKilometers(segment.LengthRadians);
// return the end profile
if (returnEndProfile) yield return Tuple.Create(NearestBottomProfileDistanceTo(bottomProfile, endDistance), endProfile);
}
public static void CreateBellhopEnvironment(string outputDirectory, string name,
double sourceDepth, double frequency, double verticalBeamWidth, double depressionElevationAngle,
List<double> bathymetryRanges, List<double> bathymetryDepths, List<double> soundspeedDepths,
List<double> soundspeedSpeeds, List<double> receiverRanges, List<double> receiverDepths,
int sedimentType, int beamCount, double maxDepth)
{
if (!Directory.Exists(outputDirectory)) Directory.CreateDirectory(outputDirectory);
// Write the bathymetry file
var bathymetryFilename = Path.Combine(outputDirectory, name + ".bty");
using (var writer = new StreamWriter(bathymetryFilename))
{
writer.WriteLine("'C'");
writer.WriteLine(bathymetryRanges.Count);
for (var index = 0; index < bathymetryRanges.Count; index++)
writer.WriteLine("{0} {1}", bathymetryRanges[index], bathymetryDepths[index]);
}
var acousticProperties = new AcousticProperties
{
HighFrequency = (float)frequency,
LowFrequency = (float)frequency,
DepressionElevationAngle = (float)depressionElevationAngle,
SourceDepth = (float)sourceDepth,
VerticalBeamWidth = (float)verticalBeamWidth,
};
var maxRadius = (int)Math.Ceiling(receiverRanges.Last() * 1.01); // Allow an extra 1% of range so the beams don't run off the end before they hit the last column of receivers
var sspData = soundspeedDepths.Select((t, index) => new SoundSpeedSample((float)t, (float)soundspeedSpeeds[index])).ToList();
var soundSpeedProfile = new SoundSpeedProfile
{
Data = sspData
};
var result = GetRadialConfiguration(acousticProperties, soundSpeedProfile, SedimentTypes.Find(sedimentType),
maxDepth, maxRadius, receiverRanges, receiverDepths,
false, true, true, beamCount);
File.WriteAllText(Path.Combine(outputDirectory, name + ".env"), result, new ASCIIEncoding());
}
public static string GetRadialConfiguration(AcousticProperties acousticProperties, SoundSpeedProfile ssp, SedimentType sediment,
double maxDepth, double maxRadius, List<double> ranges, List<double> depths,
bool useSurfaceReflection, bool useVerticalBeamforming, bool generateArrivalsFile, int beamCount)
{
using (var sw = new StringWriter())
{
sw.WriteLine("'TL' ! Title");
sw.WriteLine("{0} ! Frequency (Hz)", acousticProperties.Frequency);
sw.WriteLine("1 ! NMedia"); // was NMEDIA in gui_genbellhopenv.m
sw.WriteLine(useSurfaceReflection ? "'CFFT ' ! Top Option" : "'CVFT ' ! Top Option");
sw.WriteLine("0 0.00 {0} ! N sigma depth", ssp.Data[ssp.Data.Count - 1].Depth);
// If SSP is shallower than the bathymetry then extrapolate an SSP entry for the deepest part of the water
//if (SSP.DepthVector[SSP.DepthVector.Length - 1] < RealBottomDepth_Meters)
// SoundSpeedProfile = ExtrapolateSSP(SoundSpeedProfile, RealBottomDepth_Meters);
foreach (var sample in ssp.Data)
sw.WriteLine("{0:0.00} {1:0.00} 0.00 1.00 0.00 0.00 / ! z c cs rho", sample.Depth, sample.SoundSpeed);
sw.WriteLine("'A*' 0.00 ! Bottom Option, sigma"); // A = Acoustic halfspace, ~ = read bathymetry file, 0.0 = bottom roughness (currently ignored)
sw.WriteLine("{0} {1} {2} {3} {4} {5} / ! lower halfspace", maxDepth, sediment.CompressionWaveSpeed, sediment.ShearWaveSpeed, sediment.Density, sediment.LossParameter, 0);
// Source and Receiver Depths and Ranges
sw.WriteLine("1"); // Number of Source Depths
sw.WriteLine("{0} /", acousticProperties.SourceDepth); // source depth
sw.WriteLine("{0}", depths.Count); // Number of Receiver Depths
foreach (var depth in depths) sw.Write("{0} ", depth);
sw.WriteLine("/ ! Receiver Depths (m)");
sw.WriteLine("{0}", ranges.Count); // Number of Receiver Ranges
foreach (var range in ranges) sw.Write("{0} ", range);
sw.WriteLine("/ ! Receiver Ranges (km)");
if (generateArrivalsFile) sw.WriteLine("'aG'"); // aB
else sw.WriteLine(useVerticalBeamforming ? "'IG*'" : "'I'");
// if useVerticalBeamforming is true, then SBPFIL must be present (Source Beam Pattern file)
sw.WriteLine("{0}", beamCount); // Number of beams
//sw.WriteLine("0"); // Number of beams
var verticalHalfAngle = acousticProperties.VerticalBeamWidth / 2;
var angle1 = acousticProperties.DepressionElevationAngle - verticalHalfAngle;
var angle2 = acousticProperties.DepressionElevationAngle + verticalHalfAngle;
sw.WriteLine("{0} {1} /", angle1, angle2); // Beam fan half-angles (negative angles are toward the surface
//sw.WriteLine("-60.00 60.00 /"); // Beam fan half-angles (negative angles are toward the surface
//sw.WriteLine("{0:F} {1:F} {2:F} ! step zbox(meters) rbox(km)", experiment.TransmissionLossSettings.DepthCellSize, RealBottomDepth_Meters + 100, (bottomProfile.Length / 1000.0) * 1.01);
sw.WriteLine("{0} {1} {2}", (ranges[0] / 2) * 1000, maxDepth, maxRadius);
return sw.ToString();
}
}
public static SoundSpeedField ReadFile(string gdemDirectory, TimePeriod month, GeoRect region)
{
var temperatureFile = NetCDFFile.Open(FindTemperatureFile(month, gdemDirectory));
var temperatureLatitudes = ((NcVarDouble)temperatureFile.Variables.Single(var => var.Name == "lat")).ToArray();
var temperatureLongitudes = ((NcVarDouble)temperatureFile.Variables.Single(var => var.Name == "lon")).ToArray();
var temperatureDepths = ((NcVarDouble)temperatureFile.Variables.Single(var => var.Name == "depth")).ToArray();
var temperatureData = ((NcVarShort)temperatureFile.Variables.Single(var => var.Name == "water_temp"));
var temperatureMissingValue = ((NcAttShort)temperatureData.Attributes.Single(att => att.Name == "missing_value"))[0];
var temperatureScaleFactor = ((NcAttFloat)temperatureData.Attributes.Single(att => att.Name == "scale_factor"))[0];
var temperatureAddOffset = ((NcAttFloat)temperatureData.Attributes.Single(att => att.Name == "add_offset"))[0];
temperatureData.Filename = FindTemperatureFile(month, gdemDirectory);
var salinityFile = NetCDFFile.Open(FindSalinityFile(month, gdemDirectory));
//var salinityLatitudes = ((NcVarDouble)salinityFile.Variables.Single(var => var.Name == "lat")).ToArray();
//var salinityLongitudes = ((NcVarDouble)salinityFile.Variables.Single(var => var.Name == "lon")).ToArray();
//var salinityDepths = ((NcVarDouble)salinityFile.Variables.Single(var => var.Name == "depth")).ToArray();
var salinityData = ((NcVarShort)salinityFile.Variables.Single(var => var.Name == "salinity"));
var salinityMissingValue = ((NcAttShort)salinityData.Attributes.Single(att => att.Name == "missing_value"))[0];
var salinityScaleFactor = ((NcAttFloat)salinityData.Attributes.Single(att => att.Name == "scale_factor"))[0];
var salinityAddOffset = ((NcAttFloat)salinityData.Attributes.Single(att => att.Name == "add_offset"))[0];
salinityData.Filename = FindSalinityFile(month, gdemDirectory);
var north = region.North;
var south = region.South;
var east = region.East;
var west = region.West;
if (temperatureLongitudes.First() > west) west += 360;
if (temperatureLongitudes.Last() < west) west -= 360;
if (temperatureLongitudes.First() > east) east += 360;
if (temperatureLongitudes.Last() < east) east -= 360;
var lonMap = new List<AxisMap>();
var latMap = new List<AxisMap>();
int i;
if (east < west)
{
for (i = 0; i < temperatureLongitudes.Length; i++)
if ((temperatureLongitudes[i] <= east) || (temperatureLongitudes[i] >= west))
lonMap.Add(new AxisMap((float)temperatureLongitudes[i], i));
}
else
{
for (i = 0; i < temperatureLongitudes.Length; i++)
if ((temperatureLongitudes[i] >= west) && (temperatureLongitudes[i] <= east))
lonMap.Add(new AxisMap((float)temperatureLongitudes[i], i));
}
for (i = 0; i < temperatureLatitudes.Length; i++) if (temperatureLatitudes[i] >= south && temperatureLatitudes[i] <= north) latMap.Add(new AxisMap((float)temperatureLatitudes[i], i));
var selectedLons = lonMap.Select(x => x.Value).ToArray();
var selectedLats = latMap.Select(y => y.Value).ToArray();
var latCount = selectedLats.Length;
var lonCount = selectedLons.Length;
var newFieldEnvironmentData = new List<SoundSpeedProfile>();
for (var lonIndex = 0; lonIndex < lonCount; lonIndex++)
{
var lon = lonMap[lonIndex].Value;
var wrappedLon = lon;
while (wrappedLon > 180) wrappedLon -= 360;
while (wrappedLon < -180) wrappedLon += 360;
var lonSourceIndex = lonMap[lonIndex].Index;
for (var latIndex = 0; latIndex < latCount; latIndex++)
{
var lat = latMap[latIndex].Value;
var latSourceIndex = latMap[latIndex].Index;
var newProfile = new SoundSpeedProfile(new Geo(lat, wrappedLon));
for (var depthIndex = 0; depthIndex < temperatureDepths.Length; depthIndex++)
{
var temperatureValue = temperatureData[(uint)depthIndex, (uint)latSourceIndex, (uint)lonSourceIndex];
var salinityValue = salinityData[(uint)depthIndex, (uint)latSourceIndex, (uint)lonSourceIndex];
if ((Math.Abs(temperatureValue - temperatureMissingValue) < 0.0001) || (Math.Abs(salinityValue - salinityMissingValue) < 0.0001)) break;
var temperature = (temperatureValue * temperatureScaleFactor) + temperatureAddOffset;
var salinity = (salinityValue * salinityScaleFactor) + salinityAddOffset;
newProfile.Add(new SoundSpeedSample((float)temperatureDepths[depthIndex], temperature, salinity,
ChenMilleroLi.SoundSpeed(newProfile, (float)temperatureDepths[depthIndex], temperature, salinity)));
}
if (newProfile.Data.Count > 0) newFieldEnvironmentData.Add(newProfile);
}
}
var newField = new SoundSpeedField { TimePeriod = month };
newField.EnvironmentData.AddRange(newFieldEnvironmentData);
newField.EnvironmentData.Sort();
newField.EnvironmentData.TrimToNearestPoints(region);
return newField;
}