courselog.gpsutils
Class PositionTracer

java.lang.Object
  courselog.gpsutils.PositionTracer

All Implemented Interfaces:

ewe.ui.EventListener

public class PositionTracer
extends java.lang.Object
implements ewe.ui.EventListener

Traces the position obtained by a SerialGPSConnection into a logging file. Also provides calculations of the current duration, cumulative distance, average speed, average heading. About PositionTracer status : STATUS_OFF : The tracer is off, no recording. STATUS_RECORDING : The tracer is recording ReceiverEvents and generating trace. STATUS_HOLD : The tracer is on hold. If it restarts, a new Receiver may be activated, anyway, old records will be kept. Useful when the recorder is activated from time to time. STATUS_PAUSED : The tracer is not recording. Moves are not considered part of the trace. Useful when you are stopping your treck and want to make moves that are not interesting to record.

Field Summary

protected byte[]	buff Static buffer where logged data is written (256 chars).
java.lang.String	fileLogName Name of the logging file.
ewe.io.FileOutputStream	fLog Logging file.
protected boolean	isNextLogForced Flag to force next point to be logged, whatever the state.
protected boolean	isOutOfPause Flag indicating that next update of trace should consider that it is out of pause mode.
protected double	lastDownwards Last downwards value taken for reference.
double	lastReferenceAltitude Previous reference altitude.
TrackPoint	lastSignificantPoint Previous point, spaced at least by minDistance from current point.
protected double	lastUpwards Last upwards value taken for reference.
double	minAltitudeDifference Minimum altitude to count difference points.
double	minDistance Minimum distance between logged points.
TrackPoint	myCurrent Current point of the trace.
SerialGPSConnection	myGPS Connected GPS receiver.
int	myStatus PositionTracer status, see constants.
TrackRecord	myTrack Record of the current.
static int	OPT_STATUSCHANGED Option indicating that the receiver state has changed
static int	OPT_TRACECHANGED Option indicating that the track has changed
static int	STATUS_HOLD Status when PositionTracer is on hold (==2).
static int	STATUS_OFF Status when PositionTracer is not active (==0).
static int	STATUS_PAUSED Status when PositionTracer is paused (==3).
static int	STATUS_RECORDING Status when PositionTracer is not recording (==1).
protected ewe.util.Vector	vDisplayer Event Listener when state of the Tracer changes.

Constructor Summary

PositionTracer(SerialGPSConnection sGPS, int newStatus, java.lang.String logName)
Creates a new instance of PositionTracer with a logging file

Method Summary

void	addDisplayer(XPositionDisplayer newDisp) Add a position displayer to this tracer.
int	getGPSStatus() The status of the GPS receiver.
void	initFromStateAndLog(int newStatus, java.lang.String log) Read initial attributes of this PositionTracer from a buffer content.
void	logAPoint(TrackPoint pt) Writes a point in the logging file.
void	onEvent(ewe.ui.Event rEv) Activated when a ReceiverEvent is generated by the GPS.
void	removeDisplayer(XPositionDisplayer newDisp) Remove a position displayer to this tracer.
void	setLogFileName(java.lang.String newName) Set the log file name.
void	setStatus(int newStatus) Change the status of the tracer.
boolean	updateTrace(MeasuredPoint pt) Called when a new event is received and tracer is not off, in order to update the tracer state.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

myGPS

public SerialGPSConnection myGPS

Connected GPS receiver.

vDisplayer

protected ewe.util.Vector vDisplayer

Event Listener when state of the Tracer changes. Use of a Dispatcher would have been prefered but did not work with windows 2005 Pocket (as the same code worked with Java under WinXP).

fLog

public ewe.io.FileOutputStream fLog

Logging file. Traces of points are placed here.

buff

protected byte[] buff

Static buffer where logged data is written (256 chars).

STATUS_OFF

public static final int STATUS_OFF

Status when PositionTracer is not active (==0).

See Also:

Constant Field Values

STATUS_RECORDING

public static final int STATUS_RECORDING

Status when PositionTracer is not recording (==1).

See Also:

Constant Field Values

STATUS_HOLD

public static final int STATUS_HOLD

Status when PositionTracer is on hold (==2).

See Also:

Constant Field Values

STATUS_PAUSED

public static final int STATUS_PAUSED

Status when PositionTracer is paused (==3).

See Also:

Constant Field Values

myStatus

public int myStatus

PositionTracer status, see constants. Use setStatus to set it. Read it publicly.

OPT_STATUSCHANGED

public static final int OPT_STATUSCHANGED

Option indicating that the receiver state has changed

See Also:

Constant Field Values

OPT_TRACECHANGED

public static final int OPT_TRACECHANGED

Option indicating that the track has changed

See Also:

Constant Field Values

myTrack

public TrackRecord myTrack

Record of the current.

myCurrent

public TrackPoint myCurrent

Current point of the trace.

lastSignificantPoint

public TrackPoint lastSignificantPoint

Previous point, spaced at least by minDistance from current point.

lastReferenceAltitude

public double lastReferenceAltitude

Previous reference altitude. To compare with minAltitudeDifference to count variations from current point.

lastUpwards

protected double lastUpwards

Last upwards value taken for reference.

lastDownwards

protected double lastDownwards

Last downwards value taken for reference.

isOutOfPause

protected boolean isOutOfPause

Flag indicating that next update of trace should consider that it is out of pause mode.

isNextLogForced

protected boolean isNextLogForced

Flag to force next point to be logged, whatever the state.

minDistance

public double minDistance

Minimum distance between logged points. As GPS involves measurement errors, only points separated by this distance are logged in order to reduce points in case you don't move.

minAltitudeDifference

public double minAltitudeDifference

Minimum altitude to count difference points. As GPS involves measurement errors, only altitudes separated by this distance are counted in the vertical moves in order to reduce false moves. Initial value 5.0 m.

fileLogName

public java.lang.String fileLogName

Name of the logging file.

Constructor Detail

PositionTracer

public PositionTracer(SerialGPSConnection sGPS,
                      int newStatus,
                      java.lang.String logName)

Creates a new instance of PositionTracer with a logging file

Parameters:

sGPS - GPS receiver associated to this trace.

newStatus - The status in case this tracer is created after another one.

logName - Name of the file where the log should be placed. If null, no file is written.

Method Detail

setLogFileName

public void setLogFileName(java.lang.String newName)

Set the log file name. This closes a previous log if any. Call this with newName==null to close the log file.

Parameters:

newName - New log file name.

setStatus

public void setStatus(int newStatus)

Change the status of the tracer.

Parameters:

newStatus - Should be one of STATUS_XXX values.

getGPSStatus

public int getGPSStatus()

The status of the GPS receiver.

Returns:

one value of SerialGPSConnection.STATUS_xxx.

initFromStateAndLog

public void initFromStateAndLog(int newStatus,
                                java.lang.String log)

Read initial attributes of this PositionTracer from a buffer content. Should be able to read a buffer formatted by formatInBuffer and restore the tracer status content.

 Significant fields are :
 - Date
 - Time (UTC)
 - Latitude
 - Longitude
 - Altitude
 - Total distance
 - Total time
 - Total up
 - Total down
 

A small discripancy in the usage of this hold mode : last reference altitude is the one from the last logged point, as, in continuous mode, it is the one from the last altitude used in reference.

Parameters:

newStatus - New value of status for the tracer.

log - Buffer from which we read in values.

onEvent

public void onEvent(ewe.ui.Event rEv)

Activated when a ReceiverEvent is generated by the GPS. My call its own listener with an event signalling the trace has changed.

Specified by:

onEvent in interface ewe.ui.EventListener

Parameters:

rEv - Event from the GPS.

addDisplayer

public void addDisplayer(XPositionDisplayer newDisp)

Add a position displayer to this tracer.

Parameters:

newDisp - New displayer to add.

removeDisplayer

public void removeDisplayer(XPositionDisplayer newDisp)

Remove a position displayer to this tracer.

Parameters:

newDisp - Displayer to remove.

updateTrace

public boolean updateTrace(MeasuredPoint pt)

Called when a new event is received and tracer is not off, in order to update the tracer state. If the point is distant enough from the last point, the trace log is updated.

Parameters:

pt - New point to take into account.

Returns:

True if the trace state has changed, false otherwise.

logAPoint

public void logAPoint(TrackPoint pt)

Writes a point in the logging file.

Parameters:

pt - Point to put in the log.