Garmin GPSMAP 8700 Black Box Owners Manual - Page 62

Viewing Fish Mapping Data NOTE: This feature is not available on all products or subscriptions. The Fish Mapping weather chart shows information that can help you locate fish species. 1 Select Charts > Fish Mapping. 2 If necessary, select Menu > Layers, and turn on and off information. Viewing Sea Conditions The Sea Conditions feature shows information about surface conditions, including winds, wave height, wave period, and wave direction. Select Charts > Sea Conditions. Surface Winds Surface wind vectors appear on the Sea Conditions chart using wind barbs that indicate the direction from which the wind is blowing. A wind barb is a circle with a tail. The line or flag attached to the tail of the wind barb indicates the wind speed. A short line represents 5 knots, a long line represents 10 knots, and triangle represents 50 knots. Wind Barb Wind Speed Calm 5 knots 10 knots 15 knots 20 knots 50 knots 65 knots Wave Height, Wave Period, and Wave Direction Wave heights for an area appear as variations in color. Different colors indicate different wave heights, as shown in the legend. The wave period indicates the time (in seconds) between successive waves. Wave period lines indicate areas that have the same wave period. Wave directions appear on the chart using red arrows. The direction of each arrow pointer indicates the direction in which a wave is moving. Viewing Forecast Sea Conditions Information for Another Time Period 1 Select Charts > Sea Conditions. 2 Select an option: • To view forecasted sea conditions for the next 36 hours, in 12-hour increments, select multiple times. • To view the forecasted sea conditions for the previous 36 hours, in 12-hour increments, select multiple times. Viewing Sea Temperature Information The Sea Temperature weather chart shows the present water temperature and present surface pressure conditions. Select Charts > Sea Temperature. Surface Pressure and Water Temperature Data Surface-pressure information appears as pressure isobars and pressure centers. Isobars connect points of equal pressure. Pressure readings can help to determine weather and wind conditions. High-pressure areas are generally associated with fair weather. Low-pressure areas are generally associated with clouds and the chance of precipitation. Isobars packed closely together show a strong pressure gradient. Strong pressure gradients are associated with areas of stronger winds. Pressure units are shown in millibars (mb), inches of Mercury (inHg), or hectopascals (hPa). Colored shading indicates the surface temperature of the water, as shown in the legend in the corner of the display. Changing the Sea Surface Temperature Color Range You can change the color range dynamically to view higher resolution sea surface temperature readings. 1 Select Charts > Sea Temperature > Menu > Sea Temperature. 2 Select an option: • To allow the chartplotter to adjust the temperature range automatically, select Auto Configure. The chartplotter automatically finds the lower and upper limits for the current screen, and updates the temperaturecolor scale. • To enter the lower and upper limits for the temperature range, select Lower Limit or Upper Limit, and enter the lower or upper limit. Visibility Information Visibility is the forecast maximum horizontal distance that can be seen at the surface, as shown in the legend on the left of the screen. Variations in the visibility shading show the forecast change in surface visibility. NOTE: This feature is not available on all devices and in all subscriptions. Select Charts > Visibility. Viewing Forecast Visibility Information for Another Time Period 1 Select Charts > Visibility. 2 Select an option: • To view the visibility forecast for the next 36 hours, in 12hour increments, select multiple times. • To view the visibility forecast for the previous 36 hours, in 12-hour increments, select multiple times. Viewing Buoy Reports Report readings are taken from buoys and coastal observation stations. These readings are used to determine air temperature, dew point, water temperature, tide, wave height and period, wind direction and speed, visibility, and barometric pressure. 1 From a weather chart, select . 2 Select Buoy. Viewing Local Weather Information near a Buoy You can select an area near a buoy to view forecast information. 1 From a weather chart, select a location on the chart. 2 Select Local Weather. 3 Select an option: • To view present weather conditions from a local weather service, select Current Condition. • To view a local weather forecast, select Forecast. • To view surface wind and barometric pressure information, select Sea Surface. • To view wind and wave information, select Marine Bulletin. Weather Overlay The weather overlay superimposes weather and weather-related information on the Navigation chart, the Fishing chart, and the Perspective 3D chart view. The Navigation chart and the Fishing chart can show weather radar, height of cloud tops, lightning, 54 SiriusXM Weather