public static IPoint[] AdditiveSimplifyByAreaPlus(IPoint[] points, double threshold)
{
if (points == null || points.Length == 0)
{
return(null);
}
else if (points.Length == 2)
{
return(points);
}
List <int> filtered = new List <int>();
filtered.Add(0);
int firstIndex = 0, secondIndex = 1, thirdIndex = 2;
var totalAreaCoef = SpatialUtility.IsClockwise(points) ? 1 : -1;
double tempArea = 0;
while (thirdIndex < points.Length)
{
var area = SpatialUtility.CalculateTriangleSignedArea(points[firstIndex], points[secondIndex], points[thirdIndex]);
var areaCheck2 = SpatialUtility.CalculateTriangleArea(points[firstIndex], points[(int)((firstIndex + thirdIndex) / 2.0)], points[thirdIndex]);
tempArea += area;
if (Math.Abs(tempArea) > threshold || areaCheck2 > threshold || (area * totalAreaCoef > 0))
{
tempArea = 0;
filtered.Add(secondIndex);
firstIndex = secondIndex;
}
secondIndex = thirdIndex;
thirdIndex = thirdIndex + 1;
}
if (filtered.Count == 1)
{
filtered.Add(points.Count() / 2);
}
filtered.Add(points.Length - 1);
var output1 = filtered.Select(i => points[i]).ToArray();
//if (!output1[0].Equals(output1[output1.Length - 1]))
//{
//}
return(output1);
}
public static IPoint[] AdditiveSimplifyByArea(IPoint[] points, double threshold)
{
if (points == null || points.Length == 0)
{
return(null);
}
else if (points.Length == 2)
{
return(points);
}
List <int> filtered = new List <int>();
filtered.Add(0);
int firstIndex = 0, secondIndex = 1, thirdIndex = 2;
double tempArea = 0;
while (thirdIndex < points.Length)
{
var area = SpatialUtility.CalculateTriangleSignedArea(points[firstIndex], points[secondIndex], points[thirdIndex]);
tempArea += area;
if (Math.Abs(tempArea) > threshold)
{
tempArea = 0;
filtered.Add(secondIndex);
firstIndex = secondIndex;
}
secondIndex = thirdIndex;
thirdIndex = thirdIndex + 1;
}
if (filtered.Count == 1)
{
filtered.Add(points.Count() / 2);
}
filtered.Add(points.Length - 1);
var output1 = filtered.Select(i => points[i]).ToArray();
return(output1);
}