1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
package tim.prune.data;
/**
* Abstract class to hold static calculation functions
* for gradient (like glide slope)
*/
public abstract class GradientCalculator
{
/**
* Calculate the gradient value of the track at the specified index
* @param inTrack track object
* @param inIndex index of point to calculate gradient for
* @param inValue object in which to place result of calculation
*/
public static void calculateGradient(Track inTrack, int inIndex, SpeedValue inValue)
{
inValue.setInvalid();
if (inTrack == null || inIndex < 0 || inValue == null)
{
System.err.println("Cannot calculate gradient for index " + inIndex);
return;
}
// If no altitude or it's a waypoint then no gradient either
DataPoint point = inTrack.getPoint(inIndex);
if (point == null || !point.hasAltitude() || point.isWaypoint()) {
return;
}
// If the point has horizontal and vertical speeds already then just use those
if (point.hasHSpeed() && point.hasVSpeed()) {
inValue.setValue(point.getVSpeed().getValueInMetresPerSec() / point.getHSpeed().getValueInMetresPerSec());
}
else if (!point.getSegmentStart())
{
// Use the previous track point and the next track point
DataPoint p = inTrack.getPreviousTrackPoint(inIndex-1);
DataPoint q = inTrack.getNextTrackPoint(inIndex+1);
if (p != null && q != null && !q.getSegmentStart()
&& p.hasAltitude() && q.hasAltitude())
{
final double horizRads = DataPoint.calculateRadiansBetween(p, point) +
DataPoint.calculateRadiansBetween(point, q);
final double horizDist = Distance.convertRadiansToDistance(horizRads, UnitSetLibrary.UNITS_METRES);
final double heightDiff = q.getAltitude().getMetricValue() - p.getAltitude().getMetricValue();
// Get gradient in radians
final double gradient = Math.atan2(heightDiff, horizDist);
inValue.setValue(gradient);
}
}
// otherwise, just leave value as invalid
}
}
|
