protected List<Position> computePathPositions(
Position startPosition, Position endPosition, Angle delta) {
Angle dist = LatLon.greatCircleDistance(startPosition, endPosition);
dist = dist.multiply(0.6);
Angle azimuth = LatLon.greatCircleAzimuth(startPosition, endPosition);
LatLon locA = LatLon.greatCircleEndPosition(startPosition, azimuth.add(delta), dist);
dist = dist.multiply(0.9);
LatLon locB = LatLon.greatCircleEndPosition(startPosition, azimuth.subtract(delta), dist);
return Arrays.asList(startPosition, new Position(locA, 0), new Position(locB, 0), endPosition);
}
@Test
public void testAntipodalPointsB() {
LatLon begin = LatLon.fromDegrees(-12.0, 87.0);
double azimuthRadians = Math.toRadians(-90.0);
double distanceRadians = Math.toRadians(180.0);
LatLon end = LatLon.greatCircleEndPosition(begin, azimuthRadians, distanceRadians);
assertEquals("Antipodal points B (lat)", 12.0, end.getLatitude().degrees, THRESHOLD);
assertEquals("Antipodal points B (lon)", -93.0, end.getLongitude().degrees, THRESHOLD);
}
@Test
public void testAntipodalPointsA() {
LatLon begin = LatLon.fromDegrees(53.0902505, 112.8935442);
double azimuthRadians = Math.toRadians(-90.0);
double distanceRadians = Math.toRadians(180.0);
LatLon end = LatLon.greatCircleEndPosition(begin, azimuthRadians, distanceRadians);
assertEquals("Antipodal points A (lat)", -53.0902505, end.getLatitude().degrees, THRESHOLD);
assertEquals("Antipodal points A (lon)", -67.1064558, end.getLongitude().degrees, THRESHOLD);
}
@Test
public void testTrivialAzimuthB() {
LatLon begin = LatLon.fromDegrees(0.0, 0.0);
double azimuthRadians = Math.toRadians(90.0);
double distanceRadians = Math.toRadians(360.0);
LatLon end = LatLon.greatCircleEndPosition(begin, azimuthRadians, distanceRadians);
assertEquals("Trivial Azimuth B (lat)", 0.0, end.getLatitude().degrees, THRESHOLD);
assertEquals("Trivial Azimuth B (lon)", 0.0, end.getLongitude().degrees, THRESHOLD);
}
@Test
public void testKnownPointsB() {
LatLon begin = LatLon.fromDegrees(53.0902505, 112.8935442);
double azimuthRadians = Math.toRadians(-68.4055227);
double distanceRadians = Math.toRadians(10.53630354);
LatLon end = LatLon.greatCircleEndPosition(begin, azimuthRadians, distanceRadians);
assertEquals("Known points B (lat)", 55.7426290038835, end.getLatitude().degrees, THRESHOLD);
assertEquals(
"Known points B (lon)", 95.313127193979270, end.getLongitude().degrees, THRESHOLD);
}
protected void doMoveTo(Position oldReferencePosition, Position newReferencePosition) {
java.util.ArrayList<LatLon> newLocations = new java.util.ArrayList<LatLon>();
for (LatLon ll : this.locations) {
Angle heading = LatLon.greatCircleAzimuth(oldReferencePosition, ll);
Angle pathLength = LatLon.greatCircleDistance(oldReferencePosition, ll);
newLocations.add(LatLon.greatCircleEndPosition(newReferencePosition, heading, pathLength));
}
this.setLocations(newLocations);
}
@Test
public void testKnownPointsA() {
LatLon begin = LatLon.fromDegrees(-53.0902505, -67.1064558);
double azimuthRadians = Math.toRadians(15.2204311);
double distanceRadians = Math.toRadians(-88.7560694);
LatLon end = LatLon.greatCircleEndPosition(begin, azimuthRadians, distanceRadians);
assertEquals(
"Known points A (lat)", -36.63477988750917, end.getLatitude().degrees, THRESHOLD);
assertEquals(
"Known points A (lon)", 131.98550742812412, end.getLongitude().degrees, THRESHOLD);
}
/**
* Compute the view range footprint on the globe.
*
* @param dc the current <code>DrawContext</code>
* @param steps the number of steps.
* @return an array list of <code>LatLon</code> forming a closed shape.
*/
protected ArrayList<LatLon> computeViewFootPrint(DrawContext dc, int steps) {
ArrayList<LatLon> positions = new ArrayList<LatLon>();
Position eyePos = dc.getView().getEyePosition();
Angle distance =
Angle.fromRadians(
Math.asin(
dc.getView().getFarClipDistance()
/ (dc.getGlobe().getRadius() + eyePos.getElevation())));
if (distance.degrees > 10) {
double headStep = 360d / steps;
Angle heading = Angle.ZERO;
for (int i = 0; i <= steps; i++) {
LatLon p = LatLon.greatCircleEndPosition(eyePos, heading, distance);
positions.add(p);
heading = heading.addDegrees(headStep);
}
return positions;
} else return null;
}
@Override
protected void doMoveTo(Position oldReferencePosition, Position newReferencePosition) {
if (this.boundaries.getContourCount() == 0) return;
for (int i = 0; i < this.boundaries.getContourCount(); i++) {
ArrayList<LatLon> newLocations = new ArrayList<LatLon>();
for (LatLon ll : this.boundaries.getContour(i)) {
Angle heading = LatLon.greatCircleAzimuth(oldReferencePosition, ll);
Angle pathLength = LatLon.greatCircleDistance(oldReferencePosition, ll);
newLocations.add(LatLon.greatCircleEndPosition(newReferencePosition, heading, pathLength));
}
this.boundaries.setContour(i, newLocations);
}
// We've changed the multi-polygon's list of boundaries; flag the shape as changed.
this.onShapeChanged();
}
/** {@inheritDoc} */
@Override
protected void determineLabelPositions(DrawContext dc) {
Position center = this.getReferencePosition();
if (center == null) return;
// Position the labels along a line radiating out from the center of the circle. The angle (60
// degrees) is
// chosen to match the graphic template defined by MIL-STD-2525C, pg. 613.
double globeRadius = dc.getGlobe().getRadius();
Angle labelAngle = this.getLabelAngle();
int i = 0;
for (SurfaceCircle ring : this.rings) {
double radius = ring.getRadius();
LatLon ll = LatLon.greatCircleEndPosition(center, labelAngle.radians, radius / globeRadius);
this.labels.get(i).setPosition(new Position(ll, 0));
i += 1;
}
}
protected void doMoveTo(Position oldRef, Position newRef) {
if (oldRef == null) {
String message = "nullValue.OldRefIsNull";
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
if (newRef == null) {
String message = "nullValue.NewRefIsNull";
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
super.doMoveTo(oldRef, newRef);
int count = this.locations.size();
LatLon[] newLocations = new LatLon[count];
for (int i = 0; i < count; i++) {
LatLon ll = this.locations.get(i);
double distance = LatLon.greatCircleDistance(oldRef, ll).radians;
double azimuth = LatLon.greatCircleAzimuth(oldRef, ll).radians;
newLocations[i] = LatLon.greatCircleEndPosition(newRef, azimuth, distance);
}
this.setLocations(Arrays.asList(newLocations));
}
/**
* Subdivide a list of positions so that no segment is longer then the provided maxLength. Only
* the positions between start and start + count - 1 will be processed.
*
* <p>If needed, new intermediate positions will be created along lines that follow the given
* pathType - one of Polyline.LINEAR, Polyline.RHUMB_LINE or Polyline.GREAT_CIRCLE. All position
* elevations will be either at the terrain surface if followTerrain is true, or interpolated
* according to the original elevations.
*
* @param globe the globe to draw elevations and points from.
* @param positions the original position list
* @param maxLength the maximum length for one segment.
* @param followTerrain true if the positions should be on the terrain surface.
* @param pathType the type of path to use in between two positions.
* @param start the first position indice in the original list.
* @param count how many positions from the original list have to be processed and returned.
* @return a list of positions with no segment longer then maxLength and elevations following
* terrain or not.
*/
protected static ArrayList<? extends Position> subdividePositions(
Globe globe,
ArrayList<? extends Position> positions,
double maxLength,
boolean followTerrain,
String pathType,
int start,
int count) {
if (positions == null || positions.size() < start + count) return positions;
ArrayList<Position> newPositions = new ArrayList<Position>();
// Add first position
Position pos1 = positions.get(start);
if (followTerrain)
newPositions.add(
new Position(pos1, globe.getElevation(pos1.getLatitude(), pos1.getLongitude())));
else newPositions.add(pos1);
for (int i = 1; i < count; i++) {
Position pos2 = positions.get(start + i);
double arcLengthRadians = LatLon.greatCircleDistance(pos1, pos2).radians;
double arcLength = arcLengthRadians * globe.getRadiusAt(LatLon.interpolate(.5, pos1, pos2));
if (arcLength > maxLength) {
// if necessary subdivide segment at regular intervals smaller then maxLength
Angle segmentAzimuth = null;
Angle segmentDistance = null;
int steps = (int) Math.ceil(arcLength / maxLength); // number of intervals - at least two
for (int j = 1; j < steps; j++) {
float s = (float) j / steps;
LatLon destLatLon;
if (pathType.equals(AVKey.LINEAR)) {
destLatLon = LatLon.interpolate(s, pos1, pos2);
} else if (pathType.equals(AVKey.RHUMB_LINE)) {
if (segmentAzimuth == null) {
segmentAzimuth = LatLon.rhumbAzimuth(pos1, pos2);
segmentDistance = LatLon.rhumbDistance(pos1, pos2);
}
destLatLon =
LatLon.rhumbEndPosition(pos1, segmentAzimuth.radians, s * segmentDistance.radians);
} else // GREAT_CIRCLE
{
if (segmentAzimuth == null) {
segmentAzimuth = LatLon.greatCircleAzimuth(pos1, pos2);
segmentDistance = LatLon.greatCircleDistance(pos1, pos2);
}
destLatLon =
LatLon.greatCircleEndPosition(
pos1, segmentAzimuth.radians, s * segmentDistance.radians);
}
// Set elevation
double elevation;
if (followTerrain)
elevation = globe.getElevation(destLatLon.getLatitude(), destLatLon.getLongitude());
else elevation = pos1.elevation * (1 - s) + pos2.elevation * s;
// Add new position
newPositions.add(new Position(destLatLon, elevation));
}
}
// Finally add the segment end position
if (followTerrain)
newPositions.add(
new Position(pos2, globe.getElevation(pos2.getLatitude(), pos2.getLongitude())));
else newPositions.add(pos2);
// Prepare for next segment
pos1 = pos2;
}
return newPositions;
}
