/// <summary>
/// Lookup the coordinate and compare it against all known section markers,
/// returns the best fit section
/// </summary>
/// <param name="coordinate"></param>
/// <returns></returns>
public static DlsSystem?FromLatLongCoordinate(LatLongCoordinate coordinate)
{
// This method estimates a township that is close to the coordinate.
if (!TryInferTownshipForLatLongCoordinate(coordinate, out byte meridian, out byte range, out byte township))
{
return(null);
}
//get all markers in township
var markers = DlsSurveyCoordinateProvider.Instance.TownshipMarkers(township, range, meridian);
if (markers == null)
{
return(null);
}
//each township is numbered as: there are a max of 4 markers per section with 2 floats = 144 coordinates
// some markers are empty (that section does not exist)
// 31|32|33|34|35|36
// 30|29|28|27|26|25
// 19|20|21|22|23|24
// 18|17|16|15|14|13
// 07|08|09|10|11|12
// 06|05|04|03|02|01
double bestDistance = double.MaxValue;
DlsSystem?bestDls = null;
//test each section in the town
for (byte section = 1; section <= 36; section++)
{
var dlsBoundary = markers[section - 1];
if (dlsBoundary == null || dlsBoundary.Count == 0)
{
continue; //invalid section
}
//find the center for each lsd in the section
for (byte legalSubdivision = 1; legalSubdivision <= 16; legalSubdivision++)
{
double testDistance;
switch (dlsBoundary.Count)
{
case 4:
testDistance = coordinate.RelativeDistanceTo(Interpolate4Point(legalSubdivision, dlsBoundary));
break;
default:
testDistance = double.MaxValue; //should never get here
break;
}
if (testDistance < bestDistance)
{
bestDistance = testDistance;
bestDls = new DlsSystem(legalSubdivision, section, township, range, meridian);
}
}
}
return(bestDls);
}
/// <summary>
/// Return LatLongCoordinate that represents the center of the DlsSystem
/// </summary>
/// <param name="dls">The input dls location</param>
/// <returns></returns>
public static LatLongCoordinate ToLatLong(DlsSystem dls)
{
//ask the boundary provider for a list
var dlsBoundary = DlsSurveyCoordinateProvider.Instance.BoundaryMarkers(dls.Section, dls.Township, dls.Range, dls.Meridian);
if (dlsBoundary == null || dlsBoundary.Count == 0)
{
throw new CoordinateConversionException("Invalid dls location for conversion to lat long");
}
LatLongCoordinate latLongCoordinate;
switch (dlsBoundary.Count)
{
case 4:
latLongCoordinate = Interpolate4Point(dls.LegalSubdivision, dlsBoundary);
break;
default:
throw new CoordinateConversionException($"lookup returned {dlsBoundary.Count} points");
}
return(latLongCoordinate);
}
