/**
*
*/
private HGTReader PrepReader(int res, int row, int col)
{
if (row >= readers.Length)
{
//log.error("invalid array index for row", row);
return(null);
}
if (col >= readers[row].Length)
{
//log.error("invalid array index for col", row);
return(null);
}
HGTReader rdr = readers[row][col];
if (rdr == null)
{
//statRdrNull++;
return(null);
}
// do not use if different resolution
if (res != rdr.GetRes())
{
//statRdrRes++;
return(null);
}
rdr.PrepRead();
if (row > lastRow)
{
lastRow = row;
}
return(rdr);
}
protected double GetElevation(int lat32, int lon32)
{
int row = (int)((lat32 - minLat32) * FACTOR);
int col = (int)((lon32 - minLon32) * FACTOR);
HGTReader rdr = readers[row][col];
if (rdr == null)
{
// no reader : ocean or missing file
return(outsidePolygonHeight);
}
int res = rdr.GetRes();
rdr.PrepRead();
if (res <= 0)
{
return(0); // assumed to be an area in the ocean
}
lastRow = row;
double scale = res * FACTOR;
double y1 = (lat32 - minLat32) * scale - row * res;
double x1 = (lon32 - minLon32) * scale - col * res;
int xLeft = (int)x1;
int yBottom = (int)y1;
double qx = x1 - xLeft;
double qy = y1 - yBottom;
//statPoints++;
if (useComplexInterpolation)
{
// bicubic (Catmull-Rom) interpolation with 16 points
bool filled = FillArray(rdr, row, col, xLeft, yBottom);
if (filled)
{
h = BicubicInterpolation(eleArray, qx, qy);
//statBicubic++;
}
}
if (h == HGTReader.UNDEF || !useComplexInterpolation)
{
// use bilinear interpolation if bicubic not available
int xRight = xLeft + 1;
int yTop = yBottom + 1;
int hLT = rdr.Ele(xLeft, yTop);
maxhöhe = Math.Max(maxhöhe, hLT);
minhöhe = Math.Min(minhöhe, hLT);
int hRT = rdr.Ele(xRight, yTop);
maxhöhe = Math.Max(maxhöhe, hRT);
minhöhe = Math.Min(minhöhe, hRT);
int hLB = rdr.Ele(xLeft, yBottom);
maxhöhe = Math.Max(maxhöhe, hLB);
minhöhe = Math.Min(minhöhe, hLB);
int hRB = rdr.Ele(xRight, yBottom);
maxhöhe = Math.Max(maxhöhe, hRB);
minhöhe = Math.Min(minhöhe, hRB);
h = InterpolatedHeight(qx, qy, hLT, hRT, hRB, hLB);
//statBilinear++;
//if (h == HGTReader.UNDEF) statVoid++;
}
//if (h == HGTReader.UNDEF && log.isLoggable(Level.WARNING))
//{
// double lon = lon32 * FACTOR;
// double lat = lat32 * FACTOR;
// Coord c = new Coord(lat, lon);
// log.warn("height interpolation returns void at", c.toDegreeString());
//}
return(h);
}
