// IGH -> MSTS Tile
public static TileCoordinate ConvertToTile(IghCoordinate coordinates, out double x, out double z)
{
var coord = ConvertToTile(coordinates);
x = coord.X;
z = coord.Z;
return(coord);
}
// IGH -> MSTS Precise Tile
public static PreciseTileCoordinate ConvertToTile(IghCoordinate coordinates)
{
var tileX = coordinates.Sample / 2048;
var tileZ = coordinates.Line / 2048;
var x = tileX - Math.Floor(tileX);
var z = tileZ - Math.Floor(tileZ);
Debug.Assert(z >= 0, "tileZ is off the top");
Debug.Assert(z <= 1, "tileZ is off the bottom");
Debug.Assert(x >= 0, "tileX is off the left");
Debug.Assert(x <= 1, "tileX is off the right");
return(new PreciseTileCoordinate((int)Math.Floor(tileX) - 16384, 16384 - (int)Math.Floor(tileZ) - 1, x, z));
}
// Lat/Lon -> MSTS IGH
public static IghCoordinate ConvertToIgh(LatitudeLongitudeCoordinate coordinates)
{
// Latitude/Longitude -> Line/Sample Algorithm
// Based on C code provided by the USGS, available at ftp://edcftp.cr.usgs.gov/pub/software/misc/gihll2ls.c.
// By D. Steinwand, HSTX/EROS Data Center, June, 1993.
Debug.Assert(coordinates.Latitude >= -90, "latitude is off the bottom");
Debug.Assert(coordinates.Latitude <= 90, "latitude is off the top");
Debug.Assert(coordinates.Longitude >= -180, "longitude is off the left");
Debug.Assert(coordinates.Longitude <= 180, "longitude is off the right");
double lat = coordinates.Latitude * Math.PI / 180;
double lon = coordinates.Longitude * Math.PI / 180;
int region = -1;
if (lat >= IghParallel41) /* If on or above 40 44' 11.8" */
{
if (lon <= -IghMeridian40) /* If to the left of -40 */
{
region = 0;
}
else
{
region = 2;
}
}
else if (lat >= 0.0) /* Between 0.0 and 40 44' 11.8" */
{
if (lon <= -IghMeridian40) /* If to the left of -40 */
{
region = 1;
}
else
{
region = 3;
}
}
else if (lat >= -IghParallel41) /* Between 0.0 & -40 44' 11.8" */
{
if (lon <= -IghMeridian100) /* If between -180 and -100 */
{
region = 4;
}
else if (lon <= -IghMeridian20) /* If between -100 and -20 */
{
region = 5;
}
else if (lon <= IghMeridian80) /* If between -20 and 80 */
{
region = 8;
}
else /* If between 80 and 180 */
{
region = 9;
}
}
else /* Below -40 44' 11.8" */
{
if (lon <= -IghMeridian100) /* If between -180 and -100 */
{
region = 6;
}
else if (lon <= -IghMeridian20) /* If between -100 and -20 */
{
region = 7;
}
else if (lon <= IghMeridian80) /* If between -20 and 80 */
{
region = 10;
}
else /* If between 80 and 180 */
{
region = 11;
}
}
double y = 0;
double x = 0;
if ((region == 1) || (region == 3) || (region == 4) || (region == 5) || (region == 8) || (region == 9))
{
var delta_lon = adjust_lon(lon - IghLongitudeCenter[region]);
y = lat;
x = IghLongitudeCenter[region] + delta_lon * Math.Cos(lat);
}
else
{
var delta_lon = adjust_lon(lon - IghLongitudeCenter[region]);
var theta = lat;
var constant = Math.PI * Math.Sin(lat);
/* Iterate using the Newton-Raphson method to find theta
* -----------------------------------------------------*/
for (var i = 0; ; i++)
{
var delta_theta = -(theta + Math.Sin(theta) - constant) / (1.0 + Math.Cos(theta));
theta += delta_theta;
if (Math.Abs(delta_theta) < 0.00000000001)
{
break;
}
if (i >= 30)
{
//giherror("Iteration failed to converge", "Goode-forward");
return(null);
}
}
theta /= 2.0;
y = 1.4142135623731 * Math.Sin(theta) - 0.0528035274542 * Math.Sign(lat);
x = IghLongitudeCenter[region] + 0.900316316158 * delta_lon * Math.Cos(theta);
}
Debug.Assert(y >= -Math.PI / 2, "y is off the bottom");
Debug.Assert(y <= +Math.PI / 2, "y is off the top");
Debug.Assert(x >= -Math.PI, "x is off the left");
Debug.Assert(x <= +Math.PI, "x is off the right");
var igh = new IghCoordinate(IghImageTop - y * IghRadius, x * IghRadius - IghImageLeft);
Debug.Assert(igh.Line >= 0, "line is off the top");
Debug.Assert(igh.Line <= IghImageHeight, "line is off the bottom");
Debug.Assert(igh.Sample >= 0, "line is off the left");
Debug.Assert(igh.Sample <= IghImageWidth, "line is off the right");
return(igh);
}
const double IghMeridian100 = 100d / 180 * Math.PI; // 100deg
// IGH -> Lat/Lon
public static LatitudeLongitudeCoordinate ConvertToLatLon(IghCoordinate coordinates)
{
// Line/Sample -> Latitude/Longitude Algorithm
// Based on C code provided by the USGS, available at ftp://edcftp.cr.usgs.gov/pub/software/misc/gihll2ls.c.
// By D. Steinwand, HSTX/EROS Data Center, June, 1993.
Debug.Assert(coordinates.Line >= 0, "line is off the top");
Debug.Assert(coordinates.Line <= IghImageHeight, "line is off the bottom");
Debug.Assert(coordinates.Sample >= 0, "line is off the left");
Debug.Assert(coordinates.Sample <= IghImageWidth, "line is off the right");
double y = (IghImageTop - coordinates.Line) / IghRadius;
double x = (IghImageLeft + coordinates.Sample) / IghRadius;
Debug.Assert(y >= -Math.PI / 2, "y is off the bottom");
Debug.Assert(y <= +Math.PI / 2, "y is off the top");
Debug.Assert(x >= -Math.PI, "x is off the left");
Debug.Assert(x <= +Math.PI, "x is off the right");
int region = -1;
if (y >= IghParallel41) /* If on or above 40 44' 11.8" */
{
if (x <= -IghMeridian40) /* If to the left of -40 */
{
region = 0;
}
else
{
region = 2;
}
}
else if (y >= 0.0) /* Between 0.0 and 40 44' 11.8" */
{
if (x <= -IghMeridian40) /* If to the left of -40 */
{
region = 1;
}
else
{
region = 3;
}
}
else if (y >= -IghParallel41) /* Between 0.0 & -40 44' 11.8" */
{
if (x <= -IghMeridian100) /* If between -180 and -100 */
{
region = 4;
}
else if (x <= -IghMeridian20) /* If between -100 and -20 */
{
region = 5;
}
else if (x <= IghMeridian80) /* If between -20 and 80 */
{
region = 8;
}
else /* If between 80 and 180 */
{
region = 9;
}
}
else /* Below -40 44' 11.8" */
{
if (x <= -IghMeridian100) /* If between -180 and -100 */
{
region = 6;
}
else if (x <= -IghMeridian20) /* If between -100 and -20 */
{
region = 7;
}
else if (x <= IghMeridian80) /* If between -20 and 80 */
{
region = 10;
}
else /* If between 80 and 180 */
{
region = 11;
}
}
x = x - IghLongitudeCenter[region];
double lat = 0;
double lon = 0;
if ((region == 1) || (region == 3) || (region == 4) || (region == 5) || (region == 8) || (region == 9))
{
lat = y;
if (Math.Abs(lat) > Math.PI / 2)
{
// giherror("Input data error", "Goode-inverse");
return(null);
}
double temp = Math.Abs(lat) - Math.PI / 2;
if (Math.Abs(temp) > double.Epsilon)
{
temp = IghLongitudeCenter[region] + x / Math.Cos(lat);
lon = adjust_lon(temp);
}
else
{
lon = IghLongitudeCenter[region];
}
}
else
{
double arg = (y + 0.0528035274542 * Math.Sign(y)) / 1.4142135623731;
if (Math.Abs(arg) > 1.0)
{
return(null);
}
double theta = Math.Asin(arg);
lon = IghLongitudeCenter[region] + (x / (0.900316316158 * Math.Cos(theta)));
if (lon < -Math.PI)
{
return(null);
}
arg = (2.0 * theta + Math.Sin(2.0 * theta)) / Math.PI;
if (Math.Abs(arg) > 1.0)
{
return(null);
}
lat = Math.Asin(arg);
}
///////////////////////////////////////////////////////////////////
return(new LatitudeLongitudeCoordinate(lat * 180 / Math.PI, lon * 180 / Math.PI));
}
