I'm surprised you don't know what this means. Have you actually plotted a course [ route ] using electronic maps and GPS's ?
I'm surprised you don't know what this means. Have you actually plotted a course [ route ] using electronic maps and GPS's ?
Most GPS,s mine does a Garmin.
When doing a route with all the waypoints [ could be 46 waypoints ] for the intended track from the paper charts cords LAT and Long to three decimal's places you then scan the paper charts with the path drawn - connected [on the paper charts] and observe the hazards to which ever distance the nav - skipper deems prudent to avoid, either side, in case crew fall asleep - making coffee etc. or to alert them for extra care near hazards. To do this obtain the co ords lat and longitude from the paper charts of all the hazards the vessel is going to pass close by and then enter the hazard waypoint list [GPS] and place / enter them with a code or name for the hazard [ as separate waypoints] re enter the waypoints the distance you want a alarm to sound - flash should the vessel enter the area between the hazard and the waypoint lat and longs co ordinances when using / navigating with the highway route page - screen. The hazards [ icon ] also appear automatically on the highway route path page and the marks you want to be the closest distance to.
Hazards waypoints are there permanently until removed from the list.
This is also can be done using C maps. When the route is completed, [check the route ] there is provision for the programme to scan / check [ scan route ] the route highway co ordinates path both sides simultaneously .
highway path width distance say =.250 nms
and highlights - pauses for a carry on command from the nearby hazard.
With the paper chart co ords you will notice that you are on land or on a reef at close distances, which gives you an indication that they are not accurate unless on harbour or coastal feature charts, near a shipping lane or port. Every astute navigator that uses "C" maps knows that, if plotting the information from recent dated paper charts lat & Long are adjusted for the magnetic variations annually and your GPS is adjusted to the Chart Datum like WGS 84.
The paper charts Co ords are entered [ Not so many meters from the electronic chart impression ]
C maps and electronic charts are not accurate unless on a commercial shipping lane or a commercial PORT land harbour. [ Harbour mode ]. [Coastal Mode] near a shipping lane or Commercial shipping land port. All other modes are way inaccurate.
Using the hazard way points from the paper charts show the actual position on the e chats "C" maps particularly at a time with the most satellites recognised or orientated. The More Satellites the More you can have confidence particularly if 8 or more satellites are align and the united states military are not engaged on a air strike attack or the with Iraq - Afghanistan Talban non or official fighters are about to attacked US Troops or US friendlies. The Us can manipulate the GPS Co ords or even turn them off. [The Skipper was not an American but who knows ? Which boats have Americans aboard and which that do not?]
The electronic charts can be adjusted if aligned with the port land leading markers, [ snail trail ] but that is visual and not satellite pin pointed but narrows the inaccuracy, depending on your eye sight and the helmsman steering a straight course during the exercise
[Wheel or Tiller ].
