/// <summary>
/// Parses the grid table header and returns an appropriate <see cref="GridTable"/>
/// </summary>
/// <param name="table">The grid tabel to initialize</param>
/// <returns>true if the header could be read.</returns>
internal override bool ReadHeader(GridTable table)
{
var headerBuffer = new byte[176];
using (var s = OpenGridTableStream())
{
s.Seek(_dataOffset, SeekOrigin.Current);
if (s.Read(headerBuffer, 0, 176) != 176)
{
return(false);
}
}
return(_dataOffset == 0
? ReadOverviewHeader(headerBuffer, table)
: ReadHeader(headerBuffer, table));
}
/// <summary>
/// Factory method to load a grid table
/// </summary>
/// <param name="location"></param>
/// <returns></returns>
public static GridTable Load(Uri location)
{
GridTable table;
if (!GridTables.TryGetValue(location, out table))
{
lock (GridTablesLock)
{
if (!GridTables.TryGetValue(location, out table))
{
var ext = Path.GetExtension(location.LocalPath) ?? string.Empty;
GridTableLoader loader;
switch (ext.ToLower())
{
case "":
case ".lla":
loader = new LlaGridTableLoader(location);
break;
case ".gsb":
loader = new GsbGridTableLoader(location);
break;
case ".dat":
loader = new DatGridTableLoader(location);
break;
case ".los":
loader = new LasLosGridTableLoader(location);
break;
default:
throw new ArgumentException();
}
table = new GridTable(loader);
GridTables.Add(location, table);
}
}
}
return(table);
}
internal override bool ReadHeader(GridTable table)
{
using (var stream = OpenGridTableStream())
{
var header = new byte[176];
if (stream.Read(header, 0, 176) != 176)
{
return(false);
}
table.LowerLeft = new PhiLambda
{
Phi = GetBigEndianDouble(header, 24),
Lambda = -GetBigEndianDouble(header, 72)
};
table.UpperRight = new PhiLambda
{
Phi = GetBigEndianDouble(header, 40),
Lambda = -GetBigEndianDouble(header, 56)
};
table.SizeOfGridCell = new PhiLambda
{
Phi = GetBigEndianDouble(header, 88),
Lambda = -GetBigEndianDouble(header, 104)
};
var size = table.UpperRight - table.LowerLeft;
table.NumLambdas = (int)(Math.Abs(size.Lambda) / table.SizeOfGridCell.Lambda + 0.5) + 1;
table.NumPhis = (int)(Math.Abs(size.Phi) / table.SizeOfGridCell.Phi + 0.5) + 1;
table.LowerLeft = PhiLambda.DegreesToRadians(table.LowerLeft);
table.UpperRight = PhiLambda.DegreesToRadians(table.UpperRight);
table.SizeOfGridCell = PhiLambda.DegreesToRadians(table.SizeOfGridCell);
return(true);
}
}
internal override bool ReadData(GridTable table)
{
using (var br = new BinaryReader(OpenGridTableStream()))
{
br.BaseStream.Seek(176, SeekOrigin.Current);
var coeffs = new PhiLambda[table.NumPhis][];
for (var row = 0; row < table.NumPhis; row++)
{
coeffs[row] = new PhiLambda[table.NumLambdas];
// NTV order is flipped compared with a normal CVS table
for (var col = table.NumLambdas - 1; col >= 0; col--)
{
const double degToArcSec = (Math.PI / 180) / 3600;
// shift values are given in "arc-seconds" and need to be converted to radians.
coeffs[row][col].Phi = ReadBigEndianDouble(br) * degToArcSec;
coeffs[row][col].Lambda = ReadBigEndianDouble(br) * degToArcSec;
}
}
table.Coefficients = coeffs;
return(true);
}
}
/// <summary>
/// Parses the grid table header and returns an appropriate <see cref="GridTable"/>
/// </summary>
/// <param name="table">The grid tabel to initialize</param>
/// <returns>true if the header could be read.</returns>
internal override bool ReadHeader(GridTable table)
{
using (var br = new BinaryReader(OpenGridTableStream()))
{
br.BaseStream.Seek(64, SeekOrigin.Current);
table.NumLambdas = br.ReadInt32();
table.NumPhis = br.ReadInt32();
br.ReadBytes(4);
PhiLambda ll, cs;
ll.Lambda = br.ReadSingle();
cs.Lambda = br.ReadSingle();
ll.Phi = br.ReadSingle();
cs.Phi = br.ReadSingle();
table.LowerLeft = PhiLambda.DegreesToRadians(ll);
table.SizeOfGridCell = PhiLambda.DegreesToRadians(cs);
table.UpperRight = ll + cs.Times(table.NumPhis, table.NumLambdas);
return(true);
}
}
internal void AddSubGrid(GridTable subGridTable)
{
_subGridTables.Add(subGridTable);
}
/// <summary> /// Parses the grid table data /// </summary> /// <param name="table">The table to fill</param> /// <returns>true if the data could be read.</returns> internal abstract bool ReadData(GridTable table);
/// <summary> /// Parses the grid table header and returns an appropriate <see cref="GridTable"/> /// </summary> /// <param name="table">The grid tabel to initialize</param> /// <returns>true if the header could be read.</returns> internal abstract bool ReadHeader(GridTable table);
internal override bool ReadData(GridTable table)
{
using (var sr = new StreamReader(OpenGridTableStream()))
{
//Skip first 2 lines
sr.ReadLine();
sr.ReadLine();
var phiIndex = -1;
var lambdaIndex = 0;
double phi = 0, lambda = 0;
var coeff = new PhiLambda[table.NumPhis][];
while (!sr.EndOfStream)
{
var line = sr.ReadLine();
if (string.IsNullOrEmpty(line))
{
continue;
}
var posColon = line.IndexOf(':');
string[] values;
int valueIndex;
if (posColon > 0)
{
phiIndex = int.Parse(line.Substring(0, posColon), NumberStyles.Integer);
coeff[phiIndex] = new PhiLambda[table.NumLambdas];
line = line.Substring(posColon + 1);
values = line.Split(new[] { ' ' });
lambda = ProjectionMath.ArcSecondsToRadians(long.Parse(values[0], NumberStyles.Integer));
phi = ProjectionMath.ArcSecondsToRadians(long.Parse(values[1], NumberStyles.Integer));
coeff[phiIndex][0].Phi = phi;
coeff[phiIndex][0].Lambda = lambda;
lambdaIndex = 1;
valueIndex = 2;
}
else
{
values = line.Split(new[] { ' ' });
valueIndex = 0;
}
if (phiIndex >= 0)
{
while (lambdaIndex < table.NumLambdas)
{
lambda += ProjectionMath.ArcMicroSecondsToRadians(
long.Parse(values[valueIndex++], NumberStyles.Integer));
phi += ProjectionMath.ArcMicroSecondsToRadians(
long.Parse(values[valueIndex++], NumberStyles.Integer));
coeff[phiIndex][lambdaIndex].Phi = phi;
coeff[phiIndex][lambdaIndex].Lambda = lambda;
lambdaIndex++;
}
}
}
table.Coefficients = coeff;
}
return(true);
}
