private static Helper.Coordinate GetIntersection(
Helper.Coordinate p1,
Helper.Coordinate p2,
Helper.Coordinate p3,
Helper.Coordinate p4)
{
// http://csharphelper.com/blog/2014/08/determine-where-two-lines-intersect-in-c/
// Get the segments' parameters.
var dx12 = p2.X - p1.X;
var dy12 = p2.Y - p1.Y;
var dx34 = p4.X - p3.X;
var dy34 = p4.Y - p3.Y;
// Solve for t1 and t2
var denominator = dy12 * dx34 - dx12 * dy34;
var t1 = ((p1.X - p3.X) * dy34 + (p3.Y - p1.Y) * dx34) / denominator;
if (double.IsInfinity(t1))
{
// The lines are parallel (or close enough to it).
throw new ArgumentException("Lines are parallel");
}
// Find the point of intersection.
return(new Helper.Coordinate(p1.X + dx12 * t1, p1.Y + dy12 * t1));
}
public static void AddCoordinatesToLineSf(Shapefile sfLines, Helper.Coordinate coordinate1,
Helper.Coordinate coordinate2)
{
var shp = new Shape();
if (!shp.Create(ShpfileType.SHP_POLYLINE))
{
throw new Exception("Error in creating shape. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate1.X, coordinate1.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate2.X, coordinate2.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
// Check if this line intersects other lines, if so shorten to intersection point:
var numShapes = sfLines.NumShapes;
for (var i = 0; i < numShapes; i++)
{
var shpTesting = sfLines.Shape[i];
if (!shpTesting.Crosses(shp))
{
continue;
}
var newCoordinate = GetIntersection(Helper.PointToCoordinate(shp.Point[0]),
Helper.PointToCoordinate(shp.Point[1]), Helper.PointToCoordinate(shpTesting.Point[0]),
Helper.PointToCoordinate(shpTesting.Point[1]));
// Replace point:
shp.Point[1] = Helper.CoordinateToPoint(newCoordinate);
}
if (sfLines.EditAddShape(shp) < 0)
{
throw new Exception("Error in adding shape. Error: " + sfLines.ErrorMsg[sfLines.LastErrorCode]);
}
}
private static void AddToPolygonSf(IShapefile sfPolygons, Helper.Coordinate coordinate1_1,
Helper.Coordinate coordinate1_2, Helper.Coordinate coordinate2_1, Helper.Coordinate coordinate2_2)
{
var shp = new Shape();
if (!shp.Create(ShpfileType.SHP_POLYGON))
{
throw new Exception("Error in creating shape. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate1_1.X, coordinate1_1.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate1_2.X, coordinate1_2.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate2_1.X, coordinate2_1.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (shp.AddPoint(coordinate2_2.X, coordinate2_2.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
// Closing:
if (shp.AddPoint(coordinate1_1.X, coordinate1_1.Y) < 0)
{
throw new Exception("Error in adding point. Error: " + shp.ErrorMsg[shp.LastErrorCode]);
}
if (!shp.PartIsClockWise[0])
{
shp.ReversePointsOrder(0);
}
if (!shp.IsValid)
{
shp = shp.FixUp2(tkUnitsOfMeasure.umMeters);
if (shp == null)
{
return;
}
if (!shp.IsValid)
{
throw new Exception("Error: shape is not valid. " + shp.IsValidReason);
}
}
// Check if this new shape is overlapping other shapes,
// if so clip and add that version instead:
var numShapes = sfPolygons.NumShapes;
for (var i = 0; i < numShapes; i++)
{
var shpTesting = sfPolygons.Shape[i];
// If within, don't add again:
if (shp.Within(shpTesting))
{
Debug.WriteLine("Shape is within " + i);
return;
}
// If overlaps, add only new part:
if (shp.Overlaps(shpTesting))
{
Debug.WriteLine(i + " overlaps. Touches: " + shp.Touches(shpTesting));
// TODO: Returns wrong part:
//shp = shpTesting.Clip(shp, tkClipOperation.clDifference);
//if (shp == null) return;
}
}
if (shp.ShapeType2D != ShpfileType.SHP_POLYGON)
{
return;
}
if (!shp.PartIsClockWise[0])
{
shp.ReversePointsOrder(0);
}
if (!shp.IsValid)
{
shp = shp.FixUp2(tkUnitsOfMeasure.umMeters);
if (shp == null)
{
return;
}
if (!shp.IsValid)
{
throw new Exception("Error: shape is not valid. " + shp.IsValidReason);
}
}
if (shp.ShapeType2D != ShpfileType.SHP_POLYGON)
{
return;
}
if (sfPolygons.EditAddShape(shp) < 0)
{
throw new Exception("Error in adding shape. Error: " + sfPolygons.ErrorMsg[sfPolygons.LastErrorCode]);
}
}
public void CreateSprayAreas()
{
var sfTracks = Helper.OpenShapefile(Path.Combine(@"sf", "Tracks.shp"));
var sfPoints = Helper.CreateSf(ShpfileType.SHP_POINT);
var sfLines = Helper.CreateSf(ShpfileType.SHP_POLYLINE);
var sfPolygons = Helper.CreateSf(ShpfileType.SHP_POLYGON);
// Set projection:
sfPoints.GeoProjection = sfTracks.GeoProjection.Clone();
sfLines.GeoProjection = sfTracks.GeoProjection.Clone();
sfPolygons.GeoProjection = sfTracks.GeoProjection.Clone();
var tempPath = Path.GetTempPath();
var utils = new Utils();
// Debug first track point:
var debugPoint = sfTracks.Shape[0].Point[0];
Debug.WriteLine(debugPoint.x);
Debug.WriteLine(debugPoint.y);
// Get the first shape:
var shp = sfTracks.Shape[0];
var trackLength = shp.Length;
// Get the first point:
var firstPoint = shp.Point[0];
// Save first point to result shapefile:
Helper.AddPointToPointSf(sfPoints, firstPoint);
var segmentLength = 0d; // Total lenght between the points
const int distance = 10; // Distance between points
const int length = 15; // Length of perpendicular lines
var skip = 1;
while (trackLength > segmentLength)
{
// Create next point on line:
var lastShape = sfPoints.Shape[sfPoints.NumShapes - 1];
var previousPoint = lastShape.Point[0];
var nextPoint = shp.InterpolatePoint(previousPoint, distance * skip);
Helper.AddPointToPointSf(sfPoints, nextPoint);
skip = 1; // reset
// Create perpendicular line
var angle = GetAngle(utils, previousPoint, nextPoint);
var previousPointCoordinate = new Helper.Coordinate(previousPoint.x, previousPoint.y);
var perpendicularCoordinate1 = new Helper.Coordinate(Math.Cos(angle) * length + previousPoint.x,
Math.Sin(angle) * length + previousPoint.y);
AddCoordinatesToLineSf(sfLines, previousPointCoordinate, perpendicularCoordinate1);
// Add line to other side:
var perpendicularCoordinate2 = new Helper.Coordinate(Math.Cos(angle) * -1 * length + previousPoint.x,
Math.Sin(angle) * -1 * length + previousPoint.y);
AddCoordinatesToLineSf(sfLines, previousPointCoordinate, perpendicularCoordinate2);
// Create polygon from two perpendicular lines:
var numShapes = sfLines.NumShapes;
if (numShapes >= 4)
{
Debug.WriteLine("numShapes: " + numShapes);
// Get first perpendicular line:
var shpLine1 = sfLines.Shape[numShapes - 4];
var point1_1 = shpLine1.Point[0];
var point1_2 = shpLine1.Point[1];
var shpLine3 = sfLines.Shape[numShapes - 2];
var point3_1 = shpLine3.Point[0];
var point3_2 = shpLine3.Point[1];
AddToPolygonSf(sfPolygons,
new Helper.Coordinate(point1_1.x, point1_1.y),
new Helper.Coordinate(point1_2.x, point1_2.y),
new Helper.Coordinate(point3_2.x, point3_2.y),
new Helper.Coordinate(point3_1.x, point3_1.y));
// Other side:
var shpLine2 = sfLines.Shape[numShapes - 3];
var point2_1 = shpLine2.Point[0];
var point2_2 = shpLine2.Point[1];
var shpLine4 = sfLines.Shape[numShapes - 1];
var point4_1 = shpLine4.Point[0];
var point4_2 = shpLine4.Point[1];
AddToPolygonSf(sfPolygons,
new Helper.Coordinate(point2_1.x, point2_1.y),
new Helper.Coordinate(point2_2.x, point2_2.y),
new Helper.Coordinate(point4_2.x, point4_2.y),
new Helper.Coordinate(point4_1.x, point4_1.y));
}
segmentLength += distance;
// Debug:
if (sfPolygons.NumShapes >= 33)
{
break;
}
}
// TODO: Check last point
sfTracks.Close();
Helper.SaveAsShapefile(sfPoints, Path.Combine(tempPath, "InterpolatedPoints.shp"));
Helper.SaveAsShapefile(sfLines, Path.Combine(tempPath, "PerpendicularLines.shp"));
Helper.SaveAsShapefile(sfPolygons, Path.Combine(tempPath, "SprayAreas.shp"));
}