Tracks

Viewing and Editing Tracks and Sonar Logs

·Track logs (or trails) and sonar logs are referred to as tracks after being imported into ReefMaster.

·Tracks are made up of a number of individual track points, which contain location, depth and time information. Depth and location data from track points is used to generate underwater maps.

·Tracks can be viewed and edited in the Track Edit Window.

·If the track has been imported from a compatible sonar log file, the sonar recording of the track can also be viewed in the Sonar Viewer.

·If the track has sidescan sonar data, the track's sidescan data can be viewed overlaid in the map view (Sidescan Mosaic module required).

To open a track for editing:

·Double click a track or select Edit from the context menu of one or more selected tracks in the in the Asset Library.

·Double click a track or select Edit from the context menu of a selected track in the Global View.

The Track Menu Bar

When a track is actively being edited, the track menu bar is visible:

Options available in the menu bar include exporting the track, setting the track-point palette for depth or hardness, opening the sonar viewer and showing sidescan data, if available.

Track Edit Area

When a track is opened for editing, the track is displayed in a standard Edit Window (2) and the Track menu bar (1) is displayed:

Editing Tracks

It is often required to edit tracks to remove track-points with bad depths. This can be done in a number of ways, including selecting individual track-points and deleting them, selecting a geographic range of points and filtering track-points based on depth. If the track was imported from a compatible sonar log, it is also possible to redraw track-points using the sonar image as a reference - see the Sonar Viewer from more information.

Track points

Tracks are displayed as a collection of individual track points, which are coloured to show the relative depth of the track point within the track.

The palette used to display the track-point colours can be selected using the Track Palette button in the track menu bar.

Selecting Individual Track Points

Individual track points can be selected using the left mouse button, with the mouse in Select mode. Individual track points can be deleted through the context menu, activated using the right mouse button, or by pressing the DEL key when the track-point is selected

Cropping and Deleting Track Points

Groups of Track-points can be selected by using the region-select mouse tool to draw a rectangle around the required track points. Selected track-points retain their colours, whilst track points that are not in the selection zone are coloured grey.

Once the selection is complete, a tool-bar is shown with buttons for the operations that can be performed on selected track points. These options can also be accessed via a context menu, activated by right-clicking on one of the selected track-points.

1. Crop to Range

Delete all track points other than the selected track points.

2. Delete Track Points

Delete all selected track points. This operation is the inverse of the crop command.

3. Create New Track From Selected Track Points

Create a new track using the selected track points; the current track is not modified as part of this operation.

A new asset window is shown, where a name for the new track can be entered.

This option is useful when, for example, a single large track covers several different areas of interest for mapping. New tracks can be made by selecting each area in turn, and each new track added to a different map project.

The Track Edit Panel

The Track Edit Pane provides information about the current track and extra editing functions:

1. Track Name

The track name can be set here. Asset names can be any string.

2. Track Properties

The Track Properties section includes a range of read-only information about the track, including information about any sonar channels that are present.

In addition, the properties section includes the track's Time Zone and Start Time:

1. Time Zone

The time zone of the track can be set using the drop-down list. The time zone only affects how times are displayed, not how they are stored.

2. Start Time

The start time of the track, which is the time of the first track point. This value is set during import when it is available. If the start time of the track has not been set, or is known to be incorrect, it can be set here. Track points times are represented as relative time offsets from the beginning of the track, and are important for accurate tide compensation. Changing the start time of the track will update the times of all track points within the track.

3. Track Point Depth Filter

Track points can be removed based on a depth filter, which removes all values lower or higher than specified minimum or maximum values.

Adjust the required minimum and/or maximum values using the sliders (1). The colouration of the track points in the graphical track display adjusts in response. Track points that will be eliminated as a result of the filter operation turn grey. Click the Apply button (2) to confirm the filter operation.

Note that the depth filter can be used in conjunction with the region select tool to limit the area in which the depth filtering will take place. First, select a number of track-points using the region select tool. With the selection region in place, adjust and apply the depth filter as required. Only track-points that are both within the selected region and outside of the specified depth range will be removed.

4. Tide and Water Level Offsets

When making maps from data gathered in tidal waters or over multiple trips from lakes at varying water levels, track-point depths must be adjusted to compensate.

The overall water level of the track can be adjusted up or down by a fixed amount, or have depths adjusted by depth offsets provided by a Tide Station.

Water level adjustments can be made either manually, or by using an existing Tide Station.

1. Keel Offset

A fixed depth offset that is applied to all track points in the track. This depth represents the depth under the water surface of the transducer.

2. Water Level

The overall depth of the track can be adjusted up or down by using the slider, or entering a value in the text box.

3. Tides

Tide adjustments offer greater control over simple water level offsets because depth offset values can be interpolated between any provided data points. For example, if a tide depth is provided for the beginning and end times of the track, all values between will be interpolated between the given values.

To use a tide offset values from a tide station, select the Tide Source to Tide Station and then select the appropriate tide station from the drop down list. The tide values are shown in the graph area, with the time period of the track shaded grey.

Manual Tide Adjustment

It is often easier to manually enter tide data for each recorded track, especially if the track is of short duration - in which case only a few data points may be required.

To add manual water level offsets to a track, set the Tide Source to Manual (1). A graph area is shown, with the time of the track highlighted in grey.

Depth offset values are entered using the edit area (2) at the bottom of the tide information panel. A time and depth are required for each offset. Offsets are added using the Add button (3).

Once a depth point has been entered, it appears in the depth point list. A depth point may be deleted using the Delete button shown in the data point row. To update the depth of an existing depth point, select the depth point and modify the depth in the edit area. Press the Add button to commit the change.