Below is a general discussion of how the "charts" are presented in RT3. If you wish to review the full set of actual charts used, please see Training Regions Used.
Radar Trainer 3 includes simulation of land masses as seen in radar. There are several chart regions provided with the program and custom ones can be created upon request by contacting Starpath.
The active chart is selected from the Select
Active Scenario panel. Press the down arrow to the right of the title to expand
the list of options. The various chart options are referred to as "scenarios" since
you load not only a chart but also a set of target vessels and a set of initial
conditions (See What is in a Scenario). Users can add and
remove scenarios, but those marked with an asterisk (*) are used in the Tutorial and cannot be
The Discussion button presents a brief
description of the scenario named in the box below it. You can read the
discussion of any scenario in the list without loading it. Just select the
scenario of interest and then press Discussion. Press Load Scenario
to set the active
scenario to the one listed in the box below it. Once loaded, the title will appear in the caption bar of the simulator, along with the
total width (east to west) of the loaded chart in nautical miles.
In all cases, the full extent of the active chart will
not be visible at one time. Only a section will be in view in the chart window.
Your own vessel (center vessel) must be in view in the chart window
in order to see a valid radar image in the simulator, either in the small
one to the right of the chart window, or the full screen presentation in the
The section of the chart that appears in
the Chart window can be panned using the pan buttons in the bottom
left of the screen in Chart View. Use these pan buttons to maintain proper radar
images as your center vessel approaches the edge of the chart window.
Chart Positions (Latitude and Longitude)
Vessel positions and other locations on the chart are
not given in the conventional latitude and longitude units of real charts.
Instead, we use a fictitious XY grid system to simplify the simulator functions.
For the small regions we use this does not cause any significant distortion of
readings. Positions on a chart (x,y) are in relative
coordinates referenced to the upper left corner of the chart. The location
of the top left corner in each chart is arbitrarily set at x=100 nmi, y=47
nmi. X increases toward the right, Y increases toward the top of the
chart. The full (left-right, x-extent) width in nautical miles of each chart
used is shown in the caption bar of the main program, as shown above. A chart with
width 5.41 nmi would extend in the x direction from 100
to 105.41. If the chart were square, the Y direction would extend from47 to (47-5.41)= 41.59, but note that not all charts are square.
You can read the actual location of any point on the chart by placing the cursor at the point in question and then pressing Shift + right click. The coordinates displayed are figuratively referred to as "lon" and "lat" but this is simply a schematic reminder of which is the x and which is the y coordinate. These are not latitudes and longitudes.
The radar range and VRM readings will match the chart scale which can be verified from the chart in the manner just described, but please remember and read again the Important Caution about the use of these training chart scenarios.