private static string GetProjectionName(double latitude, double longitude)
{
List <StatePlanePolygon> polygons = LoadStatePlanePolygons();
foreach (StatePlanePolygon p in polygons)
{
if (latitude >= p.minLat && latitude <= p.maxLat && longitude >= p.minLon && longitude <= p.maxLon)
{
int intersections = 0;
StatePlaneNode previousNode = null;
foreach (StatePlaneNode n in p.Nodes)
{
if (previousNode != null && DoLinesIntersect(previousNode, n, latitude, longitude))
{
intersections++;
}
previousNode = n;
}
if (DoLinesIntersect(p.Nodes[0], p.Nodes.Last(), latitude, longitude))
{
intersections++;
}
if (intersections % 2 == 1)
{
return(p.ID);
}
}
}
return("");
}
private static bool DoLinesIntersect(StatePlaneNode v1, StatePlaneNode v2, double lat, double lon)
{
StatePlaneNode v3 = new StatePlaneNode("whatev", lat, lon);
StatePlaneNode v4 = new StatePlaneNode("whatev", lat, double.MaxValue);
double m = SolveM(v1, v2);
double b = SolveB(v1, m);
double m2 = SolveM(v3, v4);
double b2 = SolveB(v3, m2);
double x = (b2 - b) / (m - m2);
double y = (m * x) + b;
if (double.IsNaN(x) || double.IsNaN(y))
{
return(false);
}
return(IsBetween(v1, v2, y, x) && IsBetween(v3, v4, y, x));
}
private static bool IsBetween(StatePlaneNode v1, StatePlaneNode v2, double lat, double lon)
{
//Handling perfectly straight in one direction lines...
if (v1.Latitude == v2.Latitude)
{
if (v1.Longitude >= v2.Longitude)
{
if (lon > v2.Longitude && lon < v1.Longitude)
{
return(true);
}
else
{
return(false);
}
}
else
{
if (lon < v2.Longitude && lon > v1.Longitude)
{
return(true);
}
else
{
return(false);
}
}
}
if (v1.Longitude == v2.Longitude)
{
if (v1.Latitude >= v2.Latitude)
{
if (lat > v2.Latitude && lat < v1.Latitude)
{
return(true);
}
else
{
return(false);
}
}
else
{
if (lat < v2.Latitude && lat > v1.Latitude)
{
return(true);
}
else
{
return(false);
}
}
}
if (v1.Latitude > v2.Latitude)
{
if (v1.Longitude > v2.Longitude)
{
if (lat < v1.Latitude && lat > v2.Latitude && lon > v2.Longitude && lon < v1.Longitude)
{
return(true);
}
else
{
return(false);
}
}
else
{
if (lat < v1.Latitude && lat > v2.Latitude && lon > v1.Longitude && lon < v2.Longitude)
{
return(true);
}
else
{
return(false);
}
}
}
else
{
if (v1.Longitude > v2.Longitude)
{
if (lat < v2.Latitude && lat > v1.Latitude && lon > v2.Longitude && lon < v1.Longitude)
{
return(true);
}
else
{
return(false);
}
}
else
{
if (lat < v2.Latitude && lat > v1.Latitude && lon > v1.Longitude && lon < v2.Longitude)
{
return(true);
}
else
{
return(false);
}
}
}
}
private static double SolveB(StatePlaneNode v1, double m)
{
return(v1.Latitude - (m * v1.Longitude));
}
private static double SolveM(StatePlaneNode v1, StatePlaneNode v2)
{
return((v2.Latitude - v1.Latitude) / (v2.Longitude - v1.Longitude));
}
private static List <StatePlanePolygon> LoadStatePlanePolygons()
{
List <StatePlanePolygon> polygons = new List <StatePlanePolygon>();
DirectoryInfo dirInfo = new DirectoryInfo(
string.Format("{0}\\Levrum\\Temp\\SRID",
Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData))
);
using (StreamReader reader = new StreamReader(dirInfo.FullName + @"\StateProjectionShapes.geojson"))
{
string geoJSON = reader.ReadToEnd();
int nodeCount = 0;
FeatureCollection features = JsonConvert.DeserializeObject <FeatureCollection>(geoJSON);
foreach (Feature subFeature in features.Features)
{
if (subFeature.Geometry is MultiPolygon)
{
foreach (GeoJSONPolygon subPolygon in (subFeature.Geometry as MultiPolygon).Coordinates)
{
StatePlanePolygon statePlanePolygon = new StatePlanePolygon();
foreach (var property in subFeature.Properties)
{
if (property.Key == "ZONENAME")
{
statePlanePolygon.ID = Convert.ToString(property.Value);
}
}
foreach (var coordinate in subPolygon.Coordinates)
{
foreach (var actualCoordinate in coordinate.Coordinates)
{
nodeCount++;
StatePlaneNode node = new StatePlaneNode(Convert.ToString(nodeCount), actualCoordinate.Latitude, actualCoordinate.Longitude);
if (node.Latitude < statePlanePolygon.minLat)
{
statePlanePolygon.minLat = node.Latitude;
}
if (node.Latitude > statePlanePolygon.maxLat)
{
statePlanePolygon.maxLat = node.Latitude;
}
if (node.Longitude < statePlanePolygon.minLon)
{
statePlanePolygon.minLon = node.Longitude;
}
if (node.Longitude > statePlanePolygon.maxLon)
{
statePlanePolygon.maxLon = node.Longitude;
}
statePlanePolygon.Nodes.Add(node);
}
}
polygons.Add(statePlanePolygon);
}
}
}
}
return(polygons);
}
