Editing tracks

Editing Tracks

GPS tracks must be editing for several reasons:

• Sometimes the gps tracks records sometimes wrong coordinates
• During a tour sometime the driver loses one's way, these wrong track sections must be deleted
• to many points are recorded
• ...

JGPSTrackEdit provides functions to optimize recorded gps tracks. For your convenience some of the functions are available by the popup menu of the map view (click the right mouse button).

Selected Track

Almost all editing functions are performed on the selected track. The selected track is highlighted in the tracks list. In the map view all points of the selected track are accentuated.
To select a track click in the tracks list on the track name.

Remove a track section

Due to loses one's way unwanted track section may exist. To remove such a track section, select first the last correct point of the track. Than choose "Point.Short Cut". The next step is to click on the first correct point after the unwanted track section. The track is now "short cut".

Reduce the number of track points (Compress a track)

Some GPS devices have limitation on the number of points a track may have. In such cases you may use the compress functionality of JGPSTrackEdit to reduce the number of points a track have.
There are several algorithms to compress a track available ("Track.Compress"). Hint: You may experiment with several of the options to obtain an optimize result.

• Remove every n-th point. This algorithm reduces the number of tracks "by force": Every n-th point of the track is removed. This options may be useful if the track has many points and you need to deliberately reduce the number of points.
• Remove all points within a given distance from the track line: This compression algorithm works as follows: Three consecutive points are consideres. The first and the third point determine the track line. If the second point has a distance less than the given distance, then this point is removed from the track. This algorithm is repeated for all triples of the track. This compression options delivers good compression results if there are many straight lines in the track.
• Remove all points which are nearer then a given distance. This algorithm calculates the distance of two consecutive points. If the distance is less than the given threshold value, then the second point is removed from the track. The algorithm is repeated for all pairs of the track. This compression options delivers good result if the point density of the track is very high.

The compression result may be copied to a newly created track. It is recommended to use this options, since you can evaluate the result of the compression. You may also combine several compression options on the track to obtain a desired compression ratio. See also [Track Menu].

Move a point

Select the point which should be moved (click on point with the left mouse button). Now choose "Point.Move selected point". A preview of the new track course will be visible dynamically as you move the mouse cursor to the new desired position of the selected point. To fix the new position of the point, click the left mouse button. Cancel this mode by pressing the Esc-key.

If you want to move more than one point then first select that point. Afterwards activate the move selected point mode by "Point.Move selected point mode". Now you can move a point each time you select a point. Cancel this mode by pressing the Esc-key.

Hint: the elevations of the moved points are not changed. If necessary use "Track.Update Elevations" to update the elevation of the moved points. See [Track Menu] for details and instructions of how to use this function.

Inserting points

To insert additional points to a track, select first the point in whose neighbourhood you want to insert points. Now choose "Point.Insert adjacent points". On each side of the point a new point is inserted in the middle of the line to the neighbour point. See also [Point Menu].

Deleting points

To delete a single point, select the point and choose "Point.Delete". To delete more points, choose "Point.Delete mode". Now you can delete an abritary number of points by clicking on the points. Cancel deleting by choosing "Point.Delete mode" again or by pressing the Esc-key.

Update elevations

GPS devices sometime record incorrect elevations. In such cases you may recalculate the eeelevations of all points of the track by the "Track.Update Elevation" function. See [Track Menu] for details and instructions of how to use this function.

Correct invalid points

Sometimes GPS devices record incorrect coordinates (e.g. Garmin Edge 705 sometimes records 0,0-coordinates in the TCX-file). Using the functions "Track.Correct Points" or "Track.remove invalid points" you may correct these errors, see [Track Menu] for details.