X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=src%2Ftim%2Fprune%2Ffunction%2Fcompress%2FTrackDetails.java;fp=src%2Ftim%2Fprune%2Ffunction%2Fcompress%2FTrackDetails.java;h=b2188619ef40bcc87675e43fd4148c20003c62f2;hp=0000000000000000000000000000000000000000;hb=ce6f2161b8596f7018d6a76bff79bc9e571f35fd;hpb=2d8cb72e84d5cc1089ce77baf1e34ea3ea2f8465

diff --git a/src/tim/prune/function/compress/TrackDetails.java b/src/tim/prune/function/compress/TrackDetails.java
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+++ b/src/tim/prune/function/compress/TrackDetails.java
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+package tim.prune.function.compress;
+
+import tim.prune.data.DataPoint;
+import tim.prune.data.Track;
+
+/**
+ * Class to hold details about a track
+ * which might be useful for compression
+ */
+public class TrackDetails
+{
+	/** Track object */
+	private Track _track = null;
+	/** Range span */
+	private double _trackSpan = -1.0;
+	/** Markers for start of segment */
+	private boolean[] _segmentStarts = null;
+	/** Markers for end of segment */
+	private boolean[] _segmentEnds = null;
+	/** Mean distance between track points in radians */
+	private double _meanRadians = 0.0;
+
+
+	/**
+	 * Constructor
+	 * @param inTrack track object
+	 */
+	public TrackDetails(Track inTrack)
+	{
+		_track = inTrack;
+	}
+
+	/**
+	 * Recalculate all details
+	 */
+	public void initialise()
+	{
+		// calculate track span
+		double xRange = _track.getXRange().getRange();
+		double yRange = _track.getYRange().getRange();
+		_trackSpan = (xRange > yRange ? xRange : yRange);
+
+		// Calculate segment starts / ends
+		int numPoints = _track.getNumPoints();
+		_segmentStarts = new boolean[numPoints];
+		_segmentEnds = new boolean[numPoints];
+		int prevTrackPointIndex = -1;
+		int numDistances = 0; double totalRadians = 0.0;
+		// Loop over points
+		for (int i=0; i<numPoints; i++)
+		{
+			DataPoint point = _track.getPoint(i);
+			if (!point.isWaypoint())
+			{
+				// track point, check for segment flag
+				if (point.getSegmentStart())
+				{
+					// set start of segment and end of previous
+					_segmentStarts[i] = true;
+					if (prevTrackPointIndex >= 0) {
+						_segmentEnds[prevTrackPointIndex] = true;
+					}
+				}
+				else {
+					// Add up distances between points within the same track segment
+					if (prevTrackPointIndex >= 0) {
+						numDistances++;
+						totalRadians += DataPoint.calculateRadiansBetween(_track.getPoint(prevTrackPointIndex), point);
+					}
+				}
+				prevTrackPointIndex = i;
+			}
+		}
+		// last segment
+		_segmentEnds[prevTrackPointIndex] = true;
+		// Mean radians between points
+		_meanRadians = totalRadians / numDistances;
+	}
+
+
+	/**
+	 * @return the track span
+	 */
+	public double getTrackSpan()
+	{
+		if (_trackSpan < 0.0) {initialise();}
+		return _trackSpan;
+	}
+
+	/**
+	 * @param inPointIndex index of point to check
+	 * @return true if specified point is start of segment
+	 */
+	public boolean isSegmentStart(int inPointIndex)
+	{
+		if (_segmentStarts == null ||
+			_segmentStarts.length != _track.getNumPoints()) {initialise();}
+		return _segmentStarts[inPointIndex];
+	}
+
+	/**
+	 * @param inPointIndex index of point to check
+	 * @return true if specified point is end of segment
+	 */
+	public boolean isSegmentEnd(int inPointIndex)
+	{
+		if (_segmentEnds == null ||
+			_segmentEnds.length != _track.getNumPoints()) {initialise();}
+		return _segmentEnds[inPointIndex];
+	}
+
+	/**
+	 * @return mean radians between adjacent track points
+	 */
+	public double getMeanRadians()
+	{
+		if (_meanRadians == 0.0) {initialise();}
+		return _meanRadians;
+	}
+}