//we don't have a line shape so we use a rectangle for these axis
public CircleImpl(Point p, double dist, SpatialContext ctx)
{
//We assume any normalization / validation of params already occurred (including bounding dist)
this.point = p;
this.distRadius = dist;
this.ctx = ctx;
this.enclosingBox = ctx.GetDistCalc().CalcBoxByDistFromPt(point, distRadius, ctx);
}
//we don't have a line shape so we use a rectangle for these axis
public CircleImpl(Point p, double radiusDEG, SpatialContext ctx)
{
//We assume any validation of params already occurred (including bounding dist)
this.ctx = ctx;
this.point = p;
this.radiusDEG = radiusDEG;
this.enclosingBox = ctx.GetDistCalc().CalcBoxByDistFromPt(point, this.radiusDEG, ctx, null);
}
private readonly GeoCircle inverseCircle; //when distance reaches > 1/2 way around the world, cache the inverse.
#endregion Fields
#region Constructors
public GeoCircle(Point p, double dist, SpatialContext ctx)
: base(p, dist, ctx)
{
Debug.Assert(ctx.IsGeo());
//In the direction of latitude (N,S), distance is the same number of degrees.
distDEG = ctx.GetDistCalc().DistanceToDegrees(distRadius);
if (distDEG > 90)
{
//--spans more than half the globe
Debug.Assert(enclosingBox.GetWidth() == 360);
double backDistDEG = 180 - distDEG;
if (backDistDEG > 0)
{
double backDistance = ctx.GetDistCalc().DegreesToDistance(backDistDEG);
//shrink inverseCircle as small as possible to avoid accidental overlap
backDistance -= Ulp(backDistance);
Point backPoint = ctx.MakePoint(GetCenter().GetX() + 180, GetCenter().GetY() + 180);
inverseCircle = new GeoCircle(backPoint, backDistance, ctx);
}
else
inverseCircle = null;//whole globe
horizAxisY = GetCenter().GetY();//although probably not used
}
else
{
inverseCircle = null;
double _horizAxisY = ctx.GetDistCalc().CalcBoxByDistFromPt_yHorizAxisDEG(GetCenter(), dist, ctx);
//some rare numeric conditioning cases can cause this to be barely beyond the box
if (_horizAxisY > enclosingBox.GetMaxY())
{
horizAxisY = enclosingBox.GetMaxY();
}
else if (_horizAxisY < enclosingBox.GetMinY())
{
horizAxisY = enclosingBox.GetMinY();
}
else
{
horizAxisY = _horizAxisY;
}
//Debug.Assert(enclosingBox.Relate_yRange(horizAxis, horizAxis, ctx).Intersects());
}
}
/// <summary>
/// Computes the distance given a shape and the {@code distErrPct}. The
/// algorithm is the fraction of the distance from the center of the query
/// shape to its furthest bounding box corner.
/// </summary>
/// <param name="shape">Mandatory.</param>
/// <param name="distErrPct">0 to 0.5</param>
/// <param name="ctx">Mandatory</param>
/// <returns>A distance (in degrees).</returns>
public static double CalcDistanceFromErrPct(Shape shape, double distErrPct, SpatialContext ctx)
{
if (distErrPct < 0 || distErrPct > 0.5)
{
throw new ArgumentException("distErrPct " + distErrPct + " must be between [0 to 0.5]", "distErrPct");
}
if (distErrPct == 0 || shape is Point)
{
return 0;
}
Rectangle bbox = shape.GetBoundingBox();
//The diagonal distance should be the same computed from any opposite corner,
// and this is the longest distance that might be occurring within the shape.
double diagonalDist = ctx.GetDistCalc().Distance(
ctx.MakePoint(bbox.GetMinX(), bbox.GetMinY()), bbox.GetMaxX(), bbox.GetMaxY());
return diagonalDist*0.5*distErrPct;
}
public double GetArea(SpatialContext ctx)
{
if (ctx == null)
{
return GetWidth()*GetHeight();
}
else
{
return ctx.GetDistCalc().Area(this);
}
}
public DistanceSimilarity(SpatialContext ctx, Point queryPoint)
{
this.queryPoint = queryPoint;
this.distCalc = ctx.GetDistCalc();
this.nullValue = (ctx.IsGeo() ? 180 : double.MaxValue);
}
public SpatialRelation Relate(Circle circle, SpatialContext ctx)
{
double crossDist = ctx.GetDistCalc().Distance(point, circle.GetCenter());
double aDist = distRadius, bDist = circle.GetRadius();
if (crossDist > aDist + bDist)
return SpatialRelation.DISJOINT;
if (crossDist < aDist && crossDist + bDist <= aDist)
return SpatialRelation.CONTAINS;
if (crossDist < bDist && crossDist + aDist <= bDist)
return SpatialRelation.WITHIN;
return SpatialRelation.INTERSECTS;
}
public double GetArea(SpatialContext ctx)
{
if (ctx == null)
{
return Math.PI*distRadius*distRadius;
}
else
{
return ctx.GetDistCalc().Area(this);
}
}
public void TestGeoCircle(SpatialContext ctx)
{
base.ctx = ctx;
//--Start with some static tests that once failed:
//Bug: numeric edge at pole, fails to init
ctx.MakeCircle(110, -12, ctx.GetDistCalc().DegreesToDistance(90 + 12));
//Bug: horizXAxis not in enclosing rectangle, assertion
ctx.MakeCircle(-44, 16, DegToDist(106));
ctx.MakeCircle(-36, -76, DegToDist(14));
ctx.MakeCircle(107, 82, DegToDist(172));
// TODO need to update this test to be valid
//{
// //Bug in which distance was being confused as being in the same coordinate system as x,y.
// double distDeltaToPole = 0.001;//1m
// double distDeltaToPoleDEG = ctx.getDistCalc().distanceToDegrees(distDeltaToPole);
// double dist = 1;//1km
// double distDEG = ctx.getDistCalc().distanceToDegrees(dist);
// Circle c = ctx.makeCircle(0, 90 - distDeltaToPoleDEG - distDEG, dist);
// Rectangle cBBox = c.getBoundingBox();
// Rectangle r = ctx.makeRect(cBBox.getMaxX() * 0.99, cBBox.getMaxX() + 1, c.getCenter().getY(), c.getCenter().getY());
// assertEquals(INTERSECTS, c.getBoundingBox().relate(r, ctx));
// assertEquals("dist != xy space", INTERSECTS, c.relate(r, ctx));//once failed here
//}
Assert.Equal(/*"nudge back circle", */ SpatialRelation.CONTAINS, ctx.MakeCircle(-150, -90, DegToDist(122)).Relate(ctx.MakeRect(0, -132, 32, 32), ctx));
Assert.Equal(/* "wrong estimate", */ SpatialRelation.DISJOINT, ctx.MakeCircle(-166, 59, 5226.2).Relate(ctx.MakeRect(36, 66, 23, 23), ctx));
Assert.Equal(/*"bad CONTAINS (dateline)",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(56, -50, 12231.5).Relate(ctx.MakeRect(108, 26, 39, 48), ctx));
Assert.Equal(/*"bad CONTAINS (backwrap2)",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(112, -3, DegToDist(91)).Relate(ctx.MakeRect(-163, 29, -38, 10), ctx));
Assert.Equal(/*"bad CONTAINS (r x-wrap)",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(-139, 47, DegToDist(80)).Relate(ctx.MakeRect(-180, 180, -3, 12), ctx));
Assert.Equal(/*"bad CONTAINS (pwrap)",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(-139, 47, DegToDist(80)).Relate(ctx.MakeRect(-180, 179, -3, 12), ctx));
Assert.Equal(/*"no-dist 1",*/ SpatialRelation.WITHIN,
ctx.MakeCircle(135, 21, 0).Relate(ctx.MakeRect(-103, -154, -47, 52), ctx));
Assert.Equal(/*"bbox <= >= -90 bug",*/ SpatialRelation.CONTAINS,
ctx.MakeCircle(-64, -84, DegToDist(124)).Relate(ctx.MakeRect(-96, 96, -10, -10), ctx));
//The horizontal axis line of a geo circle doesn't necessarily pass through c's ctr.
Assert.Equal(/*"c's horiz axis doesn't pass through ctr",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(71, -44, DegToDist(40)).Relate(ctx.MakeRect(15, 27, -62, -34), ctx));
Assert.Equal(/*"pole boundary",*/ SpatialRelation.INTERSECTS,
ctx.MakeCircle(-100, -12, DegToDist(102)).Relate(ctx.MakeRect(143, 175, 4, 32), ctx));
Assert.Equal(/*"full circle assert",*/ SpatialRelation.CONTAINS,
ctx.MakeCircle(-64, 32, DegToDist(180)).Relate(ctx.MakeRect(47, 47, -14, 90), ctx));
//--Now proceed with systematic testing:
double distToOpposeSide = ctx.GetUnits().EarthRadius() * Math.PI;
Assert.Equal(ctx.GetWorldBounds(), ctx.MakeCircle(0, 0, distToOpposeSide).GetBoundingBox());
//assertEquals(ctx.makeCircle(0,0,distToOpposeSide/2 - 500).getBoundingBox());
double[] theXs = new double[] { -180, -45, 90 };
foreach (double x in theXs)
{
double[] theYs = new double[] { -90, -45, 0, 45, 90 };
foreach (double y in theYs)
{
TestCircle(x, y, 0);
TestCircle(x, y, 500);
TestCircle(x, y, DegToDist(90));
TestCircle(x, y, ctx.GetUnits().EarthRadius() * 6);
}
}
TestCircleIntersect();
}
