Unlike the Tides and Weather tabs, Visibility displays a graphical overview of all Visibility sensors within the system/cluster.
The graphs present the most recent 12 hours of visibility data, with annotation above the plots to suggest whether conditions are improving or deteriorating. The units of visibility are converted from the units read by the sensor (usually kilometers) into Nautical Miles. The size of these recent time-series plots will vary depending on the number of visibility sensors within the system as a whole.
In the footer at the base of the screen there are two timer controls.
The first displays the system time as stored by the server. This will be represented in either UTC or a local time zone depending on the system configuration.
The second is a count down timer which indicates the number of seconds until the display window us refreshed. When the counter expires the Port-Log database will provide the latest set of sensor records to the web display. Depending on the sample frequency of the sensors, the latest data record may not change with every refresh of the web display.
Menu Options
User can move between different sections of the system. Here, "Visibility" has been selected.
All available sites with visibility sensors will be displayed as individual sub-plots.
A time-series of recent (12 hours previous) visibility data. The units here are nautical miles. At the top left, a numerical statement shoes the most recent visibility value, along with an arrow to indicate whether this is improving (pointing up) or deteriorating (pointing down).
Hovering the mouse over the lines will display the actual time and values of the observation or prediction.
A timer indicating the system time (time zone dependent on client specifications), with sunset time given as an indication of remaining light for the day.
A timer to indicate when the browser will refresh (usually every 10 seconds). If there is new data to display, this will replace values already in place upon the web page.
