/// <summary>
/// Load grids from the specified folder
/// </summary>
/// <param name="strGridsFolder"></param>
/// <param name="recursive"></param>
public void InitializeExternalGrids(string strGridsFolder, bool recursive)
{
SearchOption opt = recursive ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly;
string[] gridTypes = new[] { "*.los", "*.gsb", "*.dat", "*.lla" };
List <string> names = new List <string>();
foreach (string gridType in gridTypes)
{
string[] tmp = Directory.GetFiles(strGridsFolder, gridType, opt);
names.AddRange(tmp);
}
foreach (string s in names)
{
string coreName = "@" + Path.GetFileNameWithoutExtension(s);
if (_tables.ContainsKey(coreName))
{
continue;
}
string ext = Path.GetExtension(s).ToLower();
if (ext != ".los" && ext != ".gsb" && ext != ".dat")
{
continue;
}
if (ext == ".los" && !File.Exists(s.Replace(".los", ".las")))
{
continue;
}
NadTable nt = NadTable.FromSourceName(s, false);
_tables.Add(coreName, nt);
}
}
/// <summary>
/// Creates a new instance of NadTables
/// </summary>
public NadTables()
{
_tables = new Dictionary <string, NadTable>();
Assembly a = Assembly.GetExecutingAssembly();
string[] names = a.GetManifestResourceNames();
foreach (string s in names)
{
string[] ss = s.Split('.');
string coreName = "@" + ss[ss.Length - 2];
if (_tables.ContainsKey(coreName))
{
continue;
}
string ext = Path.GetExtension(s).ToLower();
if (ext != ".lla" && ext != ".dat" && ext != ".gsb")
{
continue;
}
Stream text = a.GetManifestResourceStream(s);
if (text == null)
{
continue;
}
NadTable nt = NadTable.FromSourceName(s);
_tables.Add(coreName, nt);
}
}
/// <summary>
/// This method parses the extension of a resource location or
/// path and creates the new NadTable type.
/// </summary>
/// <param name="location"></param>
/// <param name="embedded"></param>
/// <returns></returns>
public static NadTable FromSourceName(string location, bool embedded)
{
NadTable result = null;
string ext = Path.GetExtension(location).ToLower();
switch (ext)
{
case ".lla":
result = new LlaNadTable(location, embedded);
break;
case ".gsb":
result = new GsbNadTable(location, 0, embedded);
break;
case ".dat":
result = new DatNadTable(location, embedded);
break;
case ".los":
result = new LasLosNadTable(location, embedded);
break;
}
if (result != null)
{
result.ReadHeader();
}
return(result);
}
private static bool TryGrid(PhiLam input, NadTable table)
{
var wLam = table.LowerLeft.Lambda;
var eLam = wLam + (table.NumLambdas - 1) * table.CellSize.Lambda;
var sPhi = table.LowerLeft.Phi;
var nPhi = sPhi + (table.NumPhis - 1) * table.CellSize.Lambda;
if (input.Lambda < wLam || input.Lambda > eLam ||
input.Phi < sPhi || input.Phi > nPhi)
{
return(false);
}
return(true);
}
/// <summary>
/// Checks the edges to make sure that we are not attempting to interpolate
/// from cells that don't exist.
/// </summary>
/// <param name="iPhi">The cell index in the phi direction</param>
/// <param name="iLam">The cell index in the lambda direction</param>
/// <param name="table">The Table with the values</param>
/// <returns>A PhiLam that has the shift coefficeints.</returns>
private static PhiLam GetValue(int iPhi, int iLam, NadTable table)
{
if (iPhi < 0)
{
iPhi = 0;
}
if (iPhi >= table.NumPhis)
{
iPhi = table.NumPhis - 1;
}
if (iLam < 0)
{
iLam = 0;
}
if (iLam >= table.NumLambdas)
{
iLam = table.NumPhis - 1;
}
return(table.Cvs[iPhi][iLam]);
}
private static PhiLam NadInterpolate(PhiLam t, NadTable ct)
{
PhiLam result, remainder;
result.Phi = HUGE_VAL;
result.Lambda = HUGE_VAL;
// find indices and normalize by the cell size (so fractions range from 0 to 1)
int iLam = (int)Math.Floor(t.Lambda /= ct.CellSize.Lambda);
int iPhi = (int)Math.Floor(t.Phi /= ct.CellSize.Phi);
// use the index to determine the remainder
remainder.Lambda = t.Lambda - iLam;
remainder.Phi = t.Phi - iPhi;
//int offLam = 0; // normally we look to the right and bottom neighbor cells
//int offPhi = 0;
//if (remainder.Lambda < .5) offLam = -1; // look to cell left of the current cell
//if (remainder.Phi < .5) offPhi = -1; // look to cell above the of the current cell
//// because the fractional weights are between cells, we need to adjust the
//// "remainder" so that it is now relative to the center of the top left
//// cell, taking into account that the definition of the top left cell
//// depends on whether the original remainder was larger than .5
//remainder.Phi = (remainder.Phi > .5) ? remainder.Phi - .5 : remainder.Phi + .5;
//remainder.Lambda = (remainder.Lambda > .5) ? remainder.Lambda - .5 : remainder.Phi + .5;
if (iLam < 0)
{
if (iLam == -1 && remainder.Lambda > 0.99999999999)
{
iLam++;
remainder.Lambda = 0;
}
else
{
return(result);
}
}
else if (iLam + 1 >= ct.NumLambdas)
{
if (iLam + 1 == ct.NumLambdas && remainder.Lambda < 1e-11)
{
iLam--;
}
else
{
return(result);
}
}
if (iPhi < 0)
{
if (iPhi == -1 && remainder.Phi > 0.99999999999)
{
iPhi++;
remainder.Phi = 0;
}
else
{
return(result);
}
}
else if (iPhi + 1 >= ct.NumPhis)
{
if (iPhi + 1 == ct.NumPhis && remainder.Phi < 1e-11)
{
iPhi--;
remainder.Phi = 1;
}
else
{
return(result);
}
}
PhiLam f00 = GetValue(iPhi, iLam, ct);
PhiLam f01 = GetValue(iPhi + 1, iLam, ct);
PhiLam f10 = GetValue(iPhi, iLam + 1, ct);
PhiLam f11 = GetValue(iPhi + 1, iLam + 1, ct);
// The cell weight is equivalent to the area of a cell sized square centered
// on the actual point that overlaps with the cell.
// Since the overlap must add up to 1, any portion that does not overlap
// on the left must overlap on the right, hence (1-remainder.Lambda)
double m00 = (1 - remainder.Lambda) * (1 - remainder.Phi);
double m01 = (1 - remainder.Lambda) * remainder.Phi;
double m10 = remainder.Lambda * (1 - remainder.Phi);
double m11 = remainder.Lambda * remainder.Phi;
result.Lambda = m00 * f00.Lambda + m01 * f01.Lambda + m10 * f10.Lambda + m11 * f11.Lambda;
result.Phi = m00 * f00.Phi + m01 * f01.Phi + m10 * f10.Phi + m11 * f11.Phi;
return(result);
}
private static PhiLam Convert(PhiLam input, bool inverse, NadTable table)
{
if (input.Lambda == HUGE_VAL)
{
return(input);
}
// Normalize input to ll origin
if (!table.Filled)
{
table.FillData();
}
PhiLam tb = input;
tb.Lambda -= table.LowerLeft.Lambda;
tb.Phi -= table.LowerLeft.Phi;
tb.Lambda = Proj.Adjlon(tb.Lambda - Math.PI) + Math.PI;
PhiLam t = NadInterpolate(tb, table);
if (inverse)
{
PhiLam del, dif;
int i = MAX_TRY;
if (t.Lambda == HUGE_VAL)
{
return(t);
}
t.Lambda = tb.Lambda + t.Lambda;
t.Phi = tb.Phi - t.Phi;
do
{
del = NadInterpolate(t, table);
/* This case used to return failure, but I have
* changed it to return the first order approximation
* of the inverse shift. This avoids cases where the
* grid shift *into* this grid came from another grid.
* While we aren't returning optimally correct results
* I feel a close result in this case is better than
* no result. NFW
* To demonstrate use -112.5839956 49.4914451 against
* the NTv2 grid shift file from Canada. */
if (del.Lambda == HUGE_VAL)
{
Debug.WriteLine(ProjectionMessages.InverseShiftFailed);
break;
}
t.Lambda -= dif.Lambda = t.Lambda - del.Lambda - tb.Lambda;
t.Phi -= dif.Phi = t.Phi + del.Phi - tb.Phi;
} while (i-- > 0 && Math.Abs(dif.Lambda) > TOL && Math.Abs(dif.Phi) > TOL);
if (i < 0)
{
Debug.WriteLine(ProjectionMessages.InvShiftConvergeFailed);
t.Lambda = t.Phi = HUGE_VAL;
return(t);
}
input.Lambda = Proj.Adjlon(t.Lambda + table.LowerLeft.Lambda);
input.Phi = t.Phi + table.LowerLeft.Phi;
}
else
{
if (t.Lambda == HUGE_VAL)
{
input = t;
}
else
{
input.Lambda -= t.Lambda;
input.Phi += t.Phi;
}
}
return(input);
}
/// <summary>
/// Checks the edges to make sure that we are not attempting to interpolate
/// from cells that don't exist.
/// </summary>
/// <param name="iPhi">The cell index in the phi direction</param>
/// <param name="iLam">The cell index in the lambda direction</param>
/// <param name="table">The Table with the values</param>
/// <returns>A PhiLam that has the shift coefficeints.</returns>
private static PhiLam GetValue(int iPhi, int iLam, NadTable table)
{
if (iPhi < 0) iPhi = 0;
if (iPhi >= table.NumPhis) iPhi = table.NumPhis - 1;
if (iLam < 0) iLam = 0;
if (iLam >= table.NumLambdas) iLam = table.NumPhis - 1;
return table.Cvs[iPhi][iLam];
}
/// <summary>
///
/// </summary>
/// <param name="t"></param>
/// <param name="ct"></param>
/// <returns></returns>
private static PhiLam NadInterpolate(PhiLam t, NadTable ct)
{
PhiLam result, remainder;
result.Phi = HUGE_VAL;
result.Lambda = HUGE_VAL;
// find indices and normalize by the cell size (so fractions range from 0 to 1)
int iLam = (int)Math.Floor(t.Lambda /= ct.CellSize.Lambda);
int iPhi = (int)Math.Floor(t.Phi /= ct.CellSize.Phi);
// use the index to determine the remainder
remainder.Lambda = t.Lambda - iLam;
remainder.Phi = t.Phi - iPhi;
//int offLam = 0; // normally we look to the right and bottom neighbor cells
//int offPhi = 0;
//if (remainder.Lambda < .5) offLam = -1; // look to cell left of the current cell
//if (remainder.Phi < .5) offPhi = -1; // look to cell above the of the current cell
//// because the fractional weights are between cells, we need to adjust the
//// "remainder" so that it is now relative to the center of the top left
//// cell, taking into account that the definition of the top left cell
//// depends on whether the original remainder was larger than .5
//remainder.Phi = (remainder.Phi > .5) ? remainder.Phi - .5 : remainder.Phi + .5;
//remainder.Lambda = (remainder.Lambda > .5) ? remainder.Lambda - .5 : remainder.Phi + .5;
if (iLam < 0)
{
if (iLam == -1 && remainder.Lambda > 0.99999999999)
{
iLam++;
remainder.Lambda = 0;
}
else
{
return result;
}
}
else if (iLam + 1 >= ct.NumLambdas)
{
if (iLam + 1 == ct.NumLambdas && remainder.Lambda < 1e-11)
{
iLam--;
}
else
{
return result;
}
}
if (iPhi < 0)
{
if (iPhi == -1 && remainder.Phi > 0.99999999999)
{
iPhi++;
remainder.Phi = 0;
}
else
{
return result;
}
}
else if (iPhi + 1 >= ct.NumPhis)
{
if (iPhi + 1 == ct.NumPhis && remainder.Phi < 1e-11)
{
iPhi--;
remainder.Phi = 1;
}
else
{
return result;
}
}
PhiLam f00 = GetValue(iPhi, iLam, ct);
PhiLam f01 = GetValue(iPhi + 1, iLam, ct);
PhiLam f10 = GetValue(iPhi, iLam + 1, ct);
PhiLam f11 = GetValue(iPhi + 1, iLam + 1, ct);
// The cell weight is equivalent to the area of a cell sized square centered
// on the actual point that overlaps with the cell.
// Since the overlap must add up to 1, any portion that does not overlap
// on the left must overlap on the right, hence (1-remainder.Lambda)
double m00 = (1 - remainder.Lambda) * (1 - remainder.Phi);
double m01 = (1 - remainder.Lambda) * remainder.Phi;
double m10 = remainder.Lambda * (1 - remainder.Phi);
double m11 = remainder.Lambda * remainder.Phi;
result.Lambda = m00 * f00.Lambda + m01 * f01.Lambda + m10 * f10.Lambda + m11 * f11.Lambda;
result.Phi = m00 * f00.Phi + m01 * f01.Phi + m10 * f10.Phi + m11 * f11.Phi;
return result;
}
private static PhiLam Convert(PhiLam input, bool inverse, NadTable table)
{
if (input.Lambda == HUGE_VAL) return input;
// Normalize input to ll origin
if (!table.Filled) table.FillData();
PhiLam tb = input;
tb.Lambda -= table.LowerLeft.Lambda;
tb.Phi -= table.LowerLeft.Phi;
tb.Lambda = Proj.Adjlon(tb.Lambda - Math.PI) + Math.PI;
PhiLam t = NadInterpolate(tb, table);
if (inverse)
{
PhiLam del, dif;
int i = MAX_TRY;
if (t.Lambda == HUGE_VAL) return t;
t.Lambda = tb.Lambda + t.Lambda;
t.Phi = tb.Phi - t.Phi;
do
{
del = NadInterpolate(t, table);
/* This case used to return failure, but I have
changed it to return the first order approximation
of the inverse shift. This avoids cases where the
grid shift *into* this grid came from another grid.
While we aren't returning optimally correct results
I feel a close result in this case is better than
no result. NFW
To demonstrate use -112.5839956 49.4914451 against
the NTv2 grid shift file from Canada. */
if (del.Lambda == HUGE_VAL)
{
Debug.WriteLine(ProjectionMessages.InverseShiftFailed);
break;
}
t.Lambda -= dif.Lambda = t.Lambda - del.Lambda - tb.Lambda;
t.Phi -= dif.Phi = t.Phi + del.Phi - tb.Phi;
} while (i-- > 0 && Math.Abs(dif.Lambda) > TOL && Math.Abs(dif.Phi) > TOL);
if (i < 0)
{
Debug.WriteLine(ProjectionMessages.InvShiftConvergeFailed);
t.Lambda = t.Phi = HUGE_VAL;
return t;
}
input.Lambda = Proj.Adjlon(t.Lambda + table.LowerLeft.Lambda);
input.Phi = t.Phi + table.LowerLeft.Phi;
}
else
{
if (t.Lambda == HUGE_VAL)
{
input = t;
}
else
{
input.Lambda -= t.Lambda;
input.Phi += t.Phi;
}
}
return input;
}
/// <summary>
/// Applies either a forward or backward gridshift based on the specified name
/// </summary>
/// <param name="names"></param>
/// <param name="inverse"></param>
/// <param name="xy"></param>
/// <param name="startIndex"></param>
/// <param name="numPoints"></param>
public static void Apply(string[] names, bool inverse, double[] xy, int startIndex, long numPoints)
{
for (int i = startIndex; i < numPoints; i++)
{
PhiLam input, output;
input.Phi = xy[i * 2 + 1];
input.Lambda = xy[i * 2];
output.Phi = HUGE_VAL;
output.Lambda = HUGE_VAL;
/* keep trying till we find a Table that works from the ones listed */
foreach (string name in names)
{
if (!_shift.Tables.ContainsKey(name))
{
continue;
}
NadTable table = _shift.Tables[name];
bool found = false;
// For GSB tables, we need to check for the appropriate sub-table
if (table.SubGrids != null && table.SubGrids.Count > 1)
{
foreach (NadTable subGrid in table.SubGrids)
{
/* skip tables that don't match our point at all. */
double wLam = subGrid.LowerLeft.Lambda;
double eLam = wLam + (subGrid.NumLambdas - 1) * subGrid.CellSize.Lambda;
double sPhi = subGrid.LowerLeft.Phi;
double nPhi = sPhi + (subGrid.NumPhis - 1) * subGrid.CellSize.Lambda;
if (input.Lambda < wLam || input.Lambda > eLam ||
input.Phi < sPhi || input.Phi > nPhi)
{
continue;
}
table = subGrid;
found = true;
break;
}
if (!found)
{
continue;
}
}
else
{
/* skip tables that don't match our point at all. */
double minLam = table.LowerLeft.Lambda;
double maxLam = minLam + (table.NumLambdas - 1) * table.CellSize.Lambda;
double minPhi = table.LowerLeft.Phi;
double maxPhi = minPhi + (table.NumPhis - 1) * table.CellSize.Lambda;
if (input.Lambda < minLam || input.Lambda > maxLam ||
input.Phi < minPhi || input.Phi > maxPhi)
{
continue;
}
}
// TO DO: handle child nodes? Not sure what format would require this
output = Convert(input, inverse, table);
if (output.Lambda == HUGE_VAL)
{
Debug.WriteLine("GridShift failed");
break;
}
break;
}
if (output.Lambda == HUGE_VAL)
{
Debug.WriteLine(
"pj_apply_gridshift(): failed to find a grid shift Table for location: ("
+ xy[i * 2] * 180 / Math.PI + ", " + xy[i * 2 + 1] * 180 / Math.PI + ")");
}
else
{
xy[i * 2] = output.Lambda;
xy[i * 2 + 1] = output.Phi;
}
}
}
