private static double Distance(ref PointInt a, ref PointInt b)
{
double d1 = a.X - b.X;
double d2 = a.Y - b.Y;
return(Math.Sqrt((d1 * d1) + (d2 * d2)));
}
private static List <uint> EncodePointGeometry(List <List <PointInt> > coordList)
{
List <uint> geometry = new List <uint>();
PointInt prevCoord = new PointInt()
{
X = 0, Y = 0
};
foreach (List <PointInt> points in coordList)
{
if (points.Count == 0)
{
throw new Exception("Encoding with no points. ");
}
uint commandInteger = (MoveTo & 0x7) | ((uint)points.Count << 3);
geometry.Add(commandInteger);
for (int n = 0; n < points.Count; ++n)
{
int dx = points[n].X - prevCoord.X;
int dy = points[n].Y - prevCoord.Y;
int parameter = ZigZag.Encode(dx);
geometry.Add((uint)parameter);
parameter = ZigZag.Encode(dy);
geometry.Add((uint)parameter);
prevCoord = points[n];
}
}
return(geometry);
}
private static double Cross(ref PointInt a, ref PointInt b, ref PointInt c)
{
PointShape ab = new PointShape(b.X - a.X, b.Y - a.Y);
PointShape ac = new PointShape(c.X - a.X, c.Y - a.Y);
return((ab.X * ac.Y) - (ab.Y * ac.X));
}
private static double Dot(ref PointInt a, ref PointInt b, ref PointInt c)
{
Vertex ab = new Vertex(b.X - a.X, b.Y - a.Y);
Vertex bc = new Vertex(c.X - b.X, c.Y - b.Y);
return((ab.X * bc.X) + (ab.Y * bc.Y));
}
private static List <List <PointInt> > GetGeometry(List <uint> geom, GeometryType geomType)
{
int x = 0;
int y = 0;
var coordsList = new List <List <PointInt> >();
List <PointInt> coords = null;
var geometryCount = geom.Count;
uint length = 0;
uint command = 0;
var i = 0;
while (i < geometryCount)
{
if (length <= 0)
{
length = geom[i++];
command = length & ((1 << 3) - 1);
length = length >> 3;
}
if (length > 0)
{
if (command == MoveTo)
{
coords = new List <PointInt>();
coordsList.Add(coords);
}
}
if (command == ClosePath)
{
if (geomType != GeometryType.Point && !(coords.Count == 0))
{
coords.Add(coords[0]);
}
length--;
continue;
}
var dx = geom[i++];
var dy = geom[i++];
length--;
var ldx = ZigZag.Decode((int)dx);
var ldy = ZigZag.Decode((int)dy);
x = x + ldx;
y = y + ldy;
var coord = new PointInt()
{
X = x, Y = y
};
coords.Add(coord);
}
return(coordsList);
}
private static PointInt WorldPointToTilePoint(double pointX, double pointY, int zoomLevel, int tileSize, RectangleShape tileBoundingBox)
{
double scale = ((double)tileSize / MaxExtents.SphericalMercator.Width) * (1 << zoomLevel);
PointInt result = new PointInt()
{
X = (int)Math.Round((pointX - tileBoundingBox.LowerLeftPoint.X) * scale),
Y = (int)Math.Round((tileBoundingBox.UpperLeftPoint.Y - pointY) * scale)
};
return(result);
}
private static List <uint> EncodePolygonGeometry(List <List <PointInt> > coordList)
{
List <uint> geometry = new List <uint>();
PointInt prevCoord = new PointInt()
{
X = 0, Y = 0
};
foreach (List <PointInt> points in coordList)
{
if (points.Count == 0)
{
throw new Exception("Encoding with no points. ");
}
//start of ring
uint commandInteger = (MoveTo & 0x7) | (1 << 3);
geometry.Add(commandInteger);
int dx = points[0].X - prevCoord.X;
int dy = points[0].Y - prevCoord.Y;
int parameter = ZigZag.Encode(dx);
geometry.Add((uint)parameter);
parameter = ZigZag.Encode(dy);
geometry.Add((uint)parameter);
bool lastPointRepeated = (points[points.Count - 1].X == points[0].X && points[points.Count - 1].Y == points[0].Y);
int pointCount = lastPointRepeated ? points.Count - 2 : points.Count - 1;
//encode the rest of the points
commandInteger = (LineTo & 0x7) | ((uint)(pointCount) << 3);
geometry.Add(commandInteger);
for (int n = 1; n <= pointCount; ++n)
{
dx = points[n].X - points[n - 1].X;
dy = points[n].Y - points[n - 1].Y;
parameter = ZigZag.Encode(dx);
geometry.Add((uint)parameter);
parameter = ZigZag.Encode(dy);
geometry.Add((uint)parameter);
}
//close path
commandInteger = (ClosePath & 0x7) | (1 << 3);
geometry.Add(commandInteger);
prevCoord = points[pointCount];
}
return(geometry);
}
private static double LineSegPointDist(ref PointInt a, ref PointInt b, ref PointInt c)
{
//float dist = cross(a,b,c) / distance(a,b);
if (Dot(ref a, ref b, ref c) > 0)
{
return(Distance(ref b, ref c));
}
if (Dot(ref b, ref a, ref c) > 0)
{
return(Distance(ref a, ref c));
}
return(Math.Abs(Cross(ref a, ref b, ref c) / Distance(ref a, ref b)));
}
private static List <uint> EncodeLineGeometry(List <List <PointInt> > coordList)
{
List <uint> geometry = new List <uint>();
PointInt prevCoord = new PointInt()
{
X = 0, Y = 0
};
foreach (List <PointInt> points in coordList)
{
if (points.Count == 0)
{
throw new Exception("Encoding with no points. ");
}
//start of linestring
uint commandInteger = (MoveTo & 0x7) | (1 << 3);
geometry.Add(commandInteger);
int dx = points[0].X - prevCoord.X;
int dy = points[0].Y - prevCoord.Y;
int parameter = ZigZag.Encode(dx);
geometry.Add((uint)parameter);
parameter = ZigZag.Encode(dy);
geometry.Add((uint)parameter);
//encode the rest of the points
commandInteger = (LineTo & 0x7) | ((uint)(points.Count - 1) << 3);
geometry.Add(commandInteger);
for (int n = 1; n < points.Count; ++n)
{
dx = points[n].X - points[n - 1].X;
dy = points[n].Y - points[n - 1].Y;
parameter = ZigZag.Encode(dx);
geometry.Add((uint)parameter);
parameter = ZigZag.Encode(dy);
geometry.Add((uint)parameter);
}
prevCoord = points[points.Count - 1];
}
return(geometry);
}
private static void ProcessLineShape(int zoom, int tileSize, RectangleInt tileScreenBoundingBox, TileFeature tileFeature, MultilineShape multiLineShape, int simplificationFactor, RectangleShape tileBoundingBox)
{
foreach (LineShape line in multiLineShape.Lines)
{
PointInt[] pixelPoints = new PointInt[line.Vertices.Count];
for (int n = 0; n < line.Vertices.Count; ++n)
{
pixelPoints[n] = WorldPointToTilePoint(line.Vertices[n].X, line.Vertices[n].Y, zoom, tileSize, tileBoundingBox);
}
PointInt[] simplifiedPixelPoints = SimplifyPointData(pixelPoints, simplificationFactor);
//output count may be zero for short records at low zoom levels as
//the pixel coordinates wil be a single point after simplification
if (simplifiedPixelPoints.Length > 0)
{
List <int> clippedPoints = new List <int>();
List <int> parts = new List <int>();
ClipPolyline(simplifiedPixelPoints, tileScreenBoundingBox, clippedPoints, parts);
if (parts.Count > 0)
{
//output the clipped polyline
for (int n = 0; n < parts.Count; ++n)
{
int index1 = parts[n];
int index2 = n < parts.Count - 1 ? parts[n + 1] : clippedPoints.Count;
List <PointInt> lineString = new List <PointInt>();
tileFeature.Geometry.Add(lineString);
//clipped points store separate x/y pairs so there will be two values per measure
for (int i = index1; i < index2; i += 2)
{
lineString.Add(new PointInt(clippedPoints[i], clippedPoints[i + 1]));
}
}
}
}
}
}
private static PointInt[] SimplifyPointData(PointInt[] points, int simplificationFactor)
{
// Check for duplicates points at end after they have been converted to pixel coordinates(PointInt)
int pointCount = points.Length;
while (pointCount > 2 && (points[pointCount - 1] == points[0]))
{
--pointCount;
}
PointInt[] resultPoints;
if (pointCount <= 2)
{
resultPoints = new PointInt[pointCount];
for (int i = 0; i < resultPoints.Length; i++)
{
resultPoints[i] = points[i];
}
return(resultPoints);
}
return(SimplifyDouglasPeucker(points, simplificationFactor));
}
private static void ProcessRingShape(int zoom, int tileSize, RectangleInt tileScreenBoundingBox, TileFeature tileFeature, RingShape ringShape, int simplificationFactor, RectangleShape tileBoundingBox)
{
PointInt[] tilePoints = new PointInt[ringShape.Vertices.Count];
for (int n = 0; n < ringShape.Vertices.Count; ++n)
{
tilePoints[n] = WorldPointToTilePoint(ringShape.Vertices[n].X, ringShape.Vertices[n].Y, zoom, tileSize, tileBoundingBox);
}
PointInt[] simplifiedTilePoints = SimplifyPointData(tilePoints, simplificationFactor);
//output count may be zero for short records at low zoom levels as
//the pixel coordinates wil be a single point after simplification
if (simplifiedTilePoints.Length > 3)
{
if (simplifiedTilePoints[0] != simplifiedTilePoints[simplifiedTilePoints.Length - 1])
{
Console.WriteLine("Not Closed");
}
List <PointInt> clippedRing = ClipRingShape(simplifiedTilePoints, tileScreenBoundingBox);
if (clippedRing.Count > 3)
{
tileFeature.Geometry.Add(clippedRing);
}
}
}
private static TileFeature GetVectorTileFeature(Feature feature, int zoom, int tileSize, RectangleInt tileScreenBoundingBox, int simplificationFactor, RectangleShape tileBoundingBox)
{
TileFeature tileFeature = new TileFeature();
switch (feature.GetWellKnownType())
{
case WellKnownType.Line:
case WellKnownType.Multiline:
tileFeature.Type = GeometryType.LineString;
MultilineShape multiLineShape = new MultilineShape(feature.GetWellKnownBinary());
ProcessLineShape(zoom, tileSize, tileScreenBoundingBox, tileFeature, multiLineShape, simplificationFactor, tileBoundingBox);
break;
case WellKnownType.Polygon:
case WellKnownType.Multipolygon:
tileFeature.Type = GeometryType.Polygon;
MultipolygonShape multiPolygonShape = new MultipolygonShape(feature.GetWellKnownBinary());
foreach (PolygonShape polygonShape in multiPolygonShape.Polygons)
{
ProcessRingShape(zoom, tileSize, tileScreenBoundingBox, tileFeature, polygonShape.OuterRing, simplificationFactor, tileBoundingBox);
foreach (RingShape ringShape in polygonShape.InnerRings)
{
ProcessRingShape(zoom, tileSize, tileScreenBoundingBox, tileFeature, ringShape, simplificationFactor, tileBoundingBox);
}
}
break;
case WellKnownType.Point:
case WellKnownType.Multipoint:
tileFeature.Type = GeometryType.Point;
List <PointInt> coordinates = new List <PointInt>();
MultipointShape multiPointShape = new MultipointShape();
if (feature.GetWellKnownType() == WellKnownType.Point)
{
PointShape pointShape = new PointShape(feature.GetWellKnownBinary());
multiPointShape.Points.Add(pointShape);
}
else if (feature.GetWellKnownType() == WellKnownType.Multipoint)
{
multiPointShape = new MultipointShape(feature.GetWellKnownBinary());
}
foreach (PointShape point in multiPointShape.Points)
{
PointInt pointI = WorldPointToTilePoint(point.X, point.Y, zoom, tileSize, tileBoundingBox);
coordinates.Add(new PointInt(pointI.X, pointI.Y));
}
if (coordinates.Count > 0)
{
tileFeature.Geometry.Add(coordinates);
}
break;
default:
tileFeature.Type = GeometryType.Unknown;
break;
}
//add the record attributes
foreach (var attributes in feature.ColumnValues)
{
tileFeature.Attributes.Add(new TileAttribute(attributes.Key, attributes.Value));
}
return(tileFeature);
}
private static List <PointInt> ClipRingShape(PointInt[] inputPoints, RectangleInt tileScreenBoundingBox)
{
List <PointInt> outputList = new List <PointInt>();
List <PointInt> inputList = new List <PointInt>(inputPoints.Length);
bool previousInside;
for (int n = 0; n < inputPoints.Length; ++n)
{
inputList.Add(inputPoints[n]);
}
bool inputPolygonIsHole = IsPolygonHole(inputPoints, inputPoints.Length);
//test left
previousInside = inputList[inputList.Count - 1].X >= tileScreenBoundingBox.XMin;
for (int n = 0; n < inputList.Count; ++n)
{
PointInt currentPoint = inputList[n];
bool currentInside = currentPoint.X >= tileScreenBoundingBox.XMin;
if (currentInside != previousInside)
{
//add intersection
PointInt prevPoint = n == 0 ? inputList[inputList.Count - 1] : inputList[n - 1];
int x = tileScreenBoundingBox.XMin;
int y = prevPoint.Y + (currentPoint.Y - prevPoint.Y) * (x - prevPoint.X) / (currentPoint.X - prevPoint.X);
outputList.Add(new PointInt(x, y));
}
if (currentInside)
{
outputList.Add(currentPoint);
}
previousInside = currentInside;
}
if (outputList.Count == 0)
{
return(outputList);
}
//test top
inputList = outputList.ToList();
previousInside = inputList[inputList.Count - 1].Y <= tileScreenBoundingBox.YMax;;
outputList.Clear();
for (int n = 0; n < inputList.Count; ++n)
{
PointInt currentPoint = inputList[n];
bool currentInside = currentPoint.Y <= tileScreenBoundingBox.YMax;
if (currentInside != previousInside)
{
//add intersection
PointInt prevPoint = n == 0 ? inputList[inputList.Count - 1] : inputList[n - 1];
int y = tileScreenBoundingBox.YMax;
int x = prevPoint.X + (currentPoint.X - prevPoint.X) * (y - prevPoint.Y) / (currentPoint.Y - prevPoint.Y);
outputList.Add(new PointInt(x, y));
}
if (currentInside)
{
outputList.Add(currentPoint);
}
previousInside = currentInside;
}
if (outputList.Count == 0)
{
return(outputList);
}
//test right
inputList = outputList.ToList();
previousInside = inputList[inputList.Count - 1].X <= tileScreenBoundingBox.XMax;
outputList.Clear();
for (int n = 0; n < inputList.Count; ++n)
{
PointInt currentPoint = inputList[n];
bool currentInside = currentPoint.X <= tileScreenBoundingBox.XMax;
if (currentInside != previousInside)
{
//add intersection
PointInt prevPoint = n == 0 ? inputList[inputList.Count - 1] : inputList[n - 1];
int x = tileScreenBoundingBox.XMax;
int y = prevPoint.Y + (currentPoint.Y - prevPoint.Y) * (x - prevPoint.X) / (currentPoint.X - prevPoint.X);
outputList.Add(new PointInt(x, y));
}
if (currentInside)
{
outputList.Add(currentPoint);
}
previousInside = currentInside;
}
if (outputList.Count == 0)
{
return(outputList);
}
//test bottom
inputList = outputList.ToList();
previousInside = inputList[inputList.Count - 1].Y >= tileScreenBoundingBox.YMin;
outputList.Clear();
for (int n = 0; n < inputList.Count; ++n)
{
PointInt currentPoint = inputList[n];
bool currentInside = currentPoint.Y >= tileScreenBoundingBox.YMin;
if (currentInside != previousInside)
{
//add intersection
PointInt prevPoint = n == 0 ? inputList[inputList.Count - 1] : inputList[n - 1];
int y = tileScreenBoundingBox.YMin;
int x = prevPoint.X + (currentPoint.X - prevPoint.X) * (y - prevPoint.Y) / (currentPoint.Y - prevPoint.Y);
outputList.Add(new PointInt(x, y));
}
if (currentInside)
{
outputList.Add(currentPoint);
}
previousInside = currentInside;
}
if (outputList.Count == 0)
{
return(outputList);
}
bool clippedPolygonIsHole = IsPolygonHole(outputList, outputList.Count);
if (clippedPolygonIsHole == inputPolygonIsHole)
{
outputList.Reverse();
}
if (outputList.Count > 3 && outputList[0] != outputList[outputList.Count - 1])
{
outputList.Insert(0, outputList[0]);
}
return(outputList);
}
private static PointInt[] SimplifyDouglasPeucker(PointInt[] inputPoints, double tolerance)
{
PointInt[] resultPoints = new PointInt[inputPoints.Length];
if (inputPoints.Length < 3)
{
for (int i = 0; i < inputPoints.Length; ++i)
{
resultPoints[i] = inputPoints[i];
}
return(resultPoints);
}
Int32 firstPoint = 0;
Int32 lastPoint = inputPoints.Length - 1;
//Add the first and last index to the keepers
var reducedPointIndicies = new List <int>();
reducedPointIndicies.Add(firstPoint);
reducedPointIndicies.Add(lastPoint);
//ensure first and last point not the same
while (lastPoint >= 0 && inputPoints[firstPoint].Equals(inputPoints[lastPoint]))
{
lastPoint--;
}
DouglasPeuckerReduction(inputPoints, firstPoint, lastPoint, tolerance, reducedPointIndicies);
reducedPointIndicies.Sort();
//if only two points check if both points the same
if (reducedPointIndicies.Count == 2)
{
if (inputPoints[reducedPointIndicies[0]] == inputPoints[reducedPointIndicies[1]])
{
return(new PointInt[0]);
}
}
PointInt endPoint = inputPoints[inputPoints.Length - 1];
bool addEndpoint = endPoint == inputPoints[0];
if (addEndpoint)
{
resultPoints = new PointInt[reducedPointIndicies.Count + 1];
}
else
{
resultPoints = new PointInt[reducedPointIndicies.Count];
}
for (int n = 0; n < reducedPointIndicies.Count; ++n)
{
resultPoints[n] = inputPoints[reducedPointIndicies[n]];
}
if (addEndpoint)
{
resultPoints[reducedPointIndicies.Count] = endPoint;
}
return(resultPoints);
}