Auto Follow and Display Orientation

  • Clicking the Auto Follow button  will center the chart directly on your vessel's current location. If the the gps is working  own ship is red otherwise the icon is gray. . If zoomed out to a scal that is smaller than 1:300.000 the icons changes to , when receiving gps signals and otherwise. More about he OwnShip icon is available here.
  • The default own ship icon can be replaced by  putting a file "ownship.xpm" in the User icons shared data directory. More about this  shared directory here: Routes and Marks
  • The Auto Follow button useful for two different situations:
  1. When you have panned the map away from your current location and want to quickly move back to your vessel.
  2. When underway, this will keep the display on the chart around your vessel, with the boat at the center of the chart.
  • Note: Panning the chart will disable this mode. Simply click  again to turn Auto Follow mode back on.
  • The display can be oriented three different ways, normally it is North Up but  Course Up is an alternative. With Course Up OpenCPN uses COG, course over ground. The easiest way to change between these two modes is through the "Right Click" menu. One situation where course up might be considered is when navigating a river or a canal. The third orientation is when skew charts are displayed, they are simply shown as "Chart Up",  but an optional setting exist to show them as "North Up".
  • If the option "Show skewed raster charts as North-up" in the Settings tab, is not ticked, the right-click toggle option "Set Course Up Mode/Set North Up Mode" will be replaced by "Set Course Up/Set Chart Up", for skewed charts.
  • If an electronic compass is available in the NMEA stream the own ship icon will be orientated according to this heading. The difference can be seen on the chart if there is a cross current, for example.  The boat below is heading WNW but is being set SW. An AIS CPA, Closest Point of Approach is also visible.    
  •   This icon (blue color) to the far right in the ToolBar indicates that the display is in North Up mode.
  • The red version of the icon indicates Course Up  mode. These setting can also be controlled in the ToolBox -> Settings -> Chart Display Options ->Course Up Mode
  • Note that both the red and the blue arrows are always pointing North.
  • Look Ahead! To see more of the chart in front of the boat, activate ToolBox -> Settings -> Chart Display Options ->Look Ahead  Mode. Your own boat will no longer be in the center of the screen. Instead it will be located away from the center, in the opposite direction to your present gps course(COG).
  • Don't always Look Ahead! If you are at anchor, swinging on the hook produces random courses and low speeds.If Look Ahead is on in this situation  the chart rendering will constantly be redrawn, with the boat in all possible lookahead positions as the course changes. To prevent this kind of scenario OpenCPN works like this:
    *If the boat speed is less than 1 kt, then lookahead is disabled.
    *If boat speed is greater than 3 kts, lookahead is enabled.
    *In between 1 and 3 kts, the lookahead "distance" is adjusted smoothly.
    *If  the problems still there when doing more than 3 kts, consider using  "ToolBox->GPS-FilterNMEA Course and Speed data"  to average out the "jumpiness".
  • Show skewed raster charts as North-up. Skewed charts are normally showed "skewed up", as it is intended. If ticking this box, these charts are shown North-Up by default. In both cases, activating course up, works as expected, the difference is when course up is not on.