public void Simplfy_Items_Null_ThrowsException()
{
IEnumerable <ICoordinate> items = default(IEnumerable <ICoordinate>);
double tolerance = 2;
DouglasPeuckerFilter.Simplify(items, tolerance);
}
public void Simplfy_MaximumDistance_Negative_ThrowsException()
{
List <ICoordinate> items = new List <ICoordinate>();
items.Add(new Coordinate(0, 0.008));
double tolerance = -1;
DouglasPeuckerFilter.Simplify(items, tolerance);
}
public void Simplify_Valid_Assert()
{
/*
* http://psimpl.sourceforge.net/douglas-peucker.html
*
* A
*
* a1
* a2
* X Y
* b1
* b2
* B
*/
/*
* A is furtherest from X->Y.
* X->A
* - the distance of a1 and a2 from X->A is less than the tolerance.
* - these should be removed.
* A->Y
* - the distance of B from A->Y is greater than the tolerance.
* - B is retained.
* A->B
* - there's no points here.
* B->Y
* - the distance of b1 and b2 from B->Y is less than the tolerance.
* - these should be removed.
*/
var X = new Coordinate(0, 0);
var a1 = new Coordinate(0.00012, 0.00008);
var a2 = new Coordinate(0.0001, 0.00012);
var A = new Coordinate(0.0004, 0.0004);
var B = new Coordinate(-0.0003, 0.0007);
var b1 = new Coordinate(-0.00018, 0.0008);
var b2 = new Coordinate(-0.00011, 0.0009);
var Y = new Coordinate(0, 0.001);
List <ICoordinate> items = new List <ICoordinate>();
items.Add(X);
items.Add(a1);
items.Add(a2);
items.Add(A);
items.Add(B);
items.Add(b1);
items.Add(b2);
items.Add(Y);
double tolerance = 12;
List <ICoordinate> result = new List <ICoordinate>(DouglasPeuckerFilter.Simplify(items, tolerance));
// X and Y are retained as the start and end points.
Assert.AreEqual(X, result[0]);
Assert.AreEqual(A, result[1]);
Assert.AreEqual(B, result[2]);
Assert.AreEqual(Y, result[3]);
// Confirmation.
Assert.IsTrue(Math.Abs(GeodeticCalculator.Instance.CrossTrackDistance(A, X, Y)) > Math.Abs(GeodeticCalculator.Instance.CrossTrackDistance(B, X, Y)));
Assert.IsTrue(GeodeticCalculator.Instance.CrossTrackDistance(a1, X, A) < tolerance);
Assert.IsTrue(GeodeticCalculator.Instance.CrossTrackDistance(a2, X, A) < tolerance);
Assert.IsTrue(GeodeticCalculator.Instance.CrossTrackDistance(B, A, Y) > tolerance);
Assert.IsTrue(GeodeticCalculator.Instance.CrossTrackDistance(b1, B, Y) < tolerance);
Assert.IsTrue(GeodeticCalculator.Instance.CrossTrackDistance(b2, B, Y) < tolerance);
}
