Originally Posted by bcn
And if you use the dual canvas/split screen option? With smaller scale for overview in the secondary one?
The other funcionalitity of lights out of sight "shining" on the actual chart is not implemented. I know about one chart provider who implemented this as an "enhancement" of S-57.
Unfortunately, it doesn't cut it.. there is often limited screen real estate as it is without splitting screens. Also, the light I am specifically referring to is actually a sectored lead light demarking channel limits. There should be the ability to have the full sectors displayed on the chart. They don't necessarily need to be coloured in, however, the limits of the arc
should be depicted and should extend out on the chart to the nominal range of the light. The idea being that when navigating, a plan is made based on visual terrestrial features and local aids to nav (buoys, beacons and lights) which can then be supported by the navigational aids on board (Open CPN, RADAR). Full depiction or at least the option to display full depiction is important, what if the light is out? or there is restricted vis? or the light is obstructed? (as this specific light often is when visiting cruise
ships occupy a particular anchorage) when visually looking for it you wouldn't see it but the chart should tell you at first glance, without having to look for it that there is indeed a light of significance there, and would tell you where you are in relation to the sectors which presumably demark safe and navigable water
The attached pic is of a sectored light with a range of 15nm. To look at it on the chart at first glance it looks like an all-round light, it has an arbitrary sector displayed to signify that one exists but other than that, the sector is of no use from a navigational aspect when looking at the chart. As soon as the light is off the screen there is no indication that there are any sectors at all and certainly no way of telling where you might be in relation to them.
The second two screenshots are from a different chart display system displaying the same cells from the same provider. The first is of the light depicted at a similar scale to the open CPN
shot, the second is of arcs being shown through the anchorage area and approaches where the light is of importance.
Just my two cents.
Waitangi Lead Light.pdf