private ICollection <IGeography> calculateOverlay(IGeography geometry1, IGeography geometry2, OverlayType operation, bool p)
{
GeographyCollection egc = new GeographyCollection();
egc.Add(geometry1);
egc.Add(geometry2);
GnomonicProjection projection = GeometrySpreader.GetProjection(egc);
GeometryCollection gc = GeometrySpreader.GetGeometries(egc, projection);
OverlayCalculator oc = new OverlayCalculator();
ICollection <IGeometry> planarResult = oc.CalculateOverlay(gc[0], gc[1], operation);
egc = GeometrySpreader.GetGeographies(planarResult, projection);
return(egc);
}
private static Polygon getBoundsBuffer(GeoPolygon polygon, GnomonicProjection projection, double distance, int pointsPerCircle, bool allowParallels)
{
Polygon temp = new Polygon();
List <Polygon> partialBuffers = new List <Polygon>();
GeographyCollection geographyCollection = new GeographyCollection();
ICollection <IGeometry> unionResult = null;
int c = 0;
foreach (GeoContour contour in polygon.Contours)
{
for (int i = 0; i < contour.Vertices.Count; i++)
{
GeoPoint p = contour.Vertices[i];
GeoPolygon tempPolygon = getPointBuffer(p, Math.Abs(distance), pointsPerCircle);
geographyCollection.Clear();
geographyCollection.Add(tempPolygon);
GeometryCollection gc = GeometrySpreader.GetGeometries(geographyCollection, projection);
if (gc[0] is Polygon)
{
unionResult = temp.Union((Polygon)gc[0]);
}
if (unionResult.Count > 0)
{
temp = (Polygon)((GeometryCollection)unionResult)[0];
}
c++;
if (c == 3)
{
partialBuffers.Add(temp);
temp = new Polygon();
c = 0;
}
}
}
if (temp.CoordinateCount > 0)
{
partialBuffers.Add(temp);
}
return(mergePartialBuffers(partialBuffers, allowParallels));
}
private static GeoPolygon getPolygonBuffer(GeoPolygon geoPolygon, double angleDistance, int pointsPerCircle, bool allowParallels)
{
geoPolygon = (GeoPolygon)geoPolygon.Clone();
double minAngle = Math.Sin(Math.Abs(angleDistance)) * Math.Sin(Math.PI / pointsPerCircle);
geoPolygon.ReduceSegments(minAngle);
geoPolygon.Densify(minAngle);
GnomonicProjection projection;
IGeometry geometry;
projectGeography(geoPolygon, out projection, out geometry);
Polygon planePolygon = (Polygon)geometry;
Polygon boundaryBuffer = getBoundsBuffer(geoPolygon, projection, angleDistance, pointsPerCircle, allowParallels);
ICollection <IGeometry> result;
if (angleDistance > 0)
{
result = planePolygon.Union(boundaryBuffer);
}
else
{
result = planePolygon.Difference(boundaryBuffer);
}
GeographyCollection geographyCollection = GeometrySpreader.GetGeographies(result, projection);
foreach (IGeography g in geographyCollection)
{
if (g is GeoPolygon)
{
return((GeoPolygon)g);
}
}
return(new GeoPolygon());
}
private static void projectGeography(IGeography geography, out GnomonicProjection projection, out IGeometry geometry)
{
GeographyCollection geographyCollection = new GeographyCollection();
geographyCollection.Add(geography);
double centerLatitude, centerLongitude;
GnomonicProjection.GetCenter(geography.ExtractPoints(), out centerLatitude, out centerLongitude);
projection = new GnomonicProjection(centerLongitude, centerLatitude);
GeometryCollection geometryCollection = GeometrySpreader.GetGeometries(geographyCollection, projection);
if (geometryCollection.Count > 0)
{
geometry = geometryCollection[0];
}
else
{
geometry = null;
}
}
private static GeoPolygon getPointBuffer(GeoPoint point, double angleDistance, int pointsPerCircle)
{
if (angleDistance < 0)
{
return(new GeoPolygon());
}
GnomonicProjection projection = new GnomonicProjection(point.L, point.Phi);
PointD planePoint = new PointD(0, 0);
Polygon planePolygon = (Polygon)planePoint.Buffer(Math.Tan(angleDistance), pointsPerCircle, false);
GeometryCollection geometryColllection = new GeometryCollection();
geometryColllection.Add(planePolygon);
GeographyCollection gc = GeometrySpreader.GetGeographies(geometryColllection, projection);
if (gc[0] is GeoPolygon)
{
return((GeoPolygon)gc[0]);
}
return(new GeoPolygon());
}
/// <summary>
/// Computes a convex hull of the specified points.
/// </summary>
/// <param name="points">Enumerator of coordinates for which convex hull should be computed</param>
/// <returns>A list containing a sequence of the convex hull points</returns>
public static IList <GeoPoint> GetConvexHull(IEnumerable <GeoPoint> points)
{
GeographyCollection geographyCollection = new GeographyCollection();
foreach (GeoPoint p in points)
{
geographyCollection.Add(p);
}
GnomonicProjection projection = GeometrySpreader.GetProjection(geographyCollection);
GeometryCollection geometryCollection = GeometrySpreader.GetGeometries(geographyCollection, projection);
List <ICoordinate> list = new List <ICoordinate>();
foreach (IGeometry g in geometryCollection)
{
list.Add(((PointD)g).Coordinate);
}
IList <ICoordinate> planarResult = PlanimetryAlgorithms.GetConvexHull(list);
geometryCollection.Clear();
foreach (ICoordinate p in planarResult)
{
geometryCollection.Add(new PointD(p));
}
geographyCollection = GeometrySpreader.GetGeographies(geometryCollection, projection);
List <GeoPoint> result = new List <GeoPoint>();
foreach (GeoPoint p in geographyCollection)
{
result.Add(p);
}
return(result);
}
private static GeoPolygon getPolylineBuffer(GeoPolyline geoPolyline, double angleDistance, int pointsPerCircle, bool allowParallels)
{
geoPolyline = (GeoPolyline)geoPolyline.Clone();
double minAngle = Math.Sin(Math.Abs(angleDistance)) * Math.Sin(Math.PI / pointsPerCircle);
geoPolyline.ReduceSegments(minAngle);
geoPolyline.Densify(minAngle);
GnomonicProjection projection;
IGeometry geometry;
projectGeography(geoPolyline, out projection, out geometry);
Polyline planePolyline = (Polyline)geometry;
GeographyCollection geographyCollection = new GeographyCollection();
Polygon temp = new Polygon();
List <Polygon> partialBuffers = new List <Polygon>();
ICollection <IGeometry> unionResult = null;
int c = 0;
foreach (GeoPath path in geoPolyline.Paths)
{
for (int i = 0; i < path.Vertices.Count - 1; i++)
{
GeoPoint p = path.Vertices[i];
GeoPolygon tempPolygon = getPointBuffer(p, angleDistance, pointsPerCircle);
geographyCollection.Clear();
geographyCollection.Add(tempPolygon);
GeometryCollection gc = GeometrySpreader.GetGeometries(geographyCollection, projection);
if (gc[0] is Polygon)
{
unionResult = temp.Union((Polygon)gc[0]);
}
if (unionResult.Count > 0)
{
temp = (Polygon)((GeometryCollection)unionResult)[0];
}
c++;
if (c == 3)
{
partialBuffers.Add(temp);
temp = new Polygon();
c = 0;
}
}
}
if (temp.CoordinateCount > 0)
{
partialBuffers.Add(temp);
}
Polygon planeBuffer = mergePartialBuffers(partialBuffers, allowParallels);
GeometryCollection geometryCollection = new GeometryCollection();
geometryCollection.Add(planeBuffer);
geographyCollection = GeometrySpreader.GetGeographies(geometryCollection, projection);
foreach (IGeography g in geographyCollection)
{
if (g is GeoPolygon)
{
return((GeoPolygon)g);
}
}
return(new GeoPolygon());
}
