When making maps from data gathered in tidal waters or from tracks gathered over multiple trips to lakes with varying water levels, track point depths need to be adjusted to compensate for changes in water levels. Track point depths within ReefMaster can be adjusted using either manually entered offset points, entered for each individual track (see Tracks), or through the use of a Tide Station.
A Tide Station is a collection of water level offset values, stored within ReefMaster, that can be used to offset the track-point depths of tracks within the workspace. Depth values between existing tide points are interpolated using a simple linear interpolation.
Data within a tide station must be imported from an external source; either from a comma-delimited text (CSV) file, or from the WXTide application.
ReefMaster does not provide tide information, nor does ReefMaster warrant that tide information imported from any suggested source is correct. Tide Station functionality within ReefMaster is simply a method of storing externally sourced tide offset data.
Lake Level Offsets
Adjusting track depths for varying lake levels typically involves using just a single depth value per track, which is most easily achieved by using a Manual Tide Offset. Adding a manual tide offset to a track is discussed in the Track Edit Window.
Creating a new Tide Station
To create a new tide station, click the New Asset button in the header of the Tides list in the Asset Library. A new tide station is created, and the Tide Station Edit Window is displayed.
The Tide Station Edit Window
The tide station edit window is split into two sections; tide tide display area (1) and the tide station properties panel (2).
The Tide Station Properties Panel
1. Tide Station Properties
Tide station properties contains a time-zone selection list and shows the times of the first and last offset point present in the current tide station.
The time-zone is used when displaying tides in the graphical display area, and is important when importing tide zone data from a text file, when the times within the file are local times (see below).
2. Import Tide Data
Tide data can be imported from comma delimited text files or the WXTide32 application.
Some principles apply whether data is imported from a text file or from WXTide:
·Tide offset data consists of a series of time-depth pairs. If, during import, a data point already exists for a specified time, it is updated with the new depth.
·Data can be mixed and matched from tide stations and data files. This can be useful for filling in missing time periods, but can also lead to errors. ReefMaster does have the capacity to warn on inconsistent tide data, it is up to the user to ensure that the data is consistent.
·If the data within a tide station needs to be updated, it is easier and safer to delete the tide station entirely and create a new one.
·The number of new or updated tide points added during an import is shown in the Status Bar once the import has completed.
Importing Tide Data from a Text File
(1) Click the import (+) button to import tide data from a text file. A file selector is shown, from where the required file can be chosen. The source file can have any file extension; by default, ReefMaster looks for files of type *.txt and *.csv.
(2) Times in the text file may be represented in local or UTC times. ReefMaster cannot determine this on its own, so ensure that the option is set correctly here. Note the time zone used is the time zone specified in the tide station properties, above. It is important that this is set correctly when importing tide values with local times.
(3) Depths within the text file may be in metres or feet. Set this option here.
Text File Format
The text file must contain one pair of values per row, in the format [TIME],[DEPTH].
·No units suffix to the depth values.
·The time can be represented in any standard format.
·There must be only one comma character per line.
·Lines that are incorrectly formatted are ignored.
After the import process has completed, the number of successfully imported tide values is displayed in the application status bar.
Importing Tide Data from WXTide
WXTide is a free program that provides tidal predictions for many areas of the world. ReefMaster can import tide information from WXTide and save it in a tide station.
WXTide can be downloaded and installed from http://www.wxtide32.com. ReefMaster needs to know the hard-disk location of the WXTide executable before it can be used. This can be done in the Global Settings or by using the Browse button (2). In a default installation, the application will be in directory “C:\Program Files (x86)\WXTide32”.
(3) A list box shows all of the available tide stations in the WXTide installation. To search for a tide station, type in the search box
(4). The list of tide stations adjusts automatically to match the entered search string.
(5) Specify the date range for the import using the two date fields, which refer to the start and end date of the import. Dates can either be typed in or selected using the data picker control. Note that importing long time periods of data may take a significant amount of time.
When the required settings have been set, start the import using the import button (1).
The Graphical Tide Display
Tide data can be viewed in the graphical tide display.
The date range of imported values is shown as a pair of read only values in the properties section.
(1) Tide data for a 24 hour period is shown in the graphical edit area. Move the mouse within the display area to show the interpolated depth value at any point in time. Hold the mouse pointer over a tide point to see the stored time and date value.
The displayed time period can be adjusted using the year (2), month (3), and day (4) arrows, or the date selector (5).
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