VGP ellipses forced to hemisphere

it would be very useful to have two additional options added for the “Set VGP Visibility” options. These would be to either force visibility to northern hemisphere or force visibility to southern hemisphere so that one can more easily see all the VGP ellipses, no matter their polarity, when adjusting plates on a sphere.


Hi Bruce,

Do you mean only draw VGP with pole positions in Northern (or Southern) hemisphere ?

And I’m assuming this is a separate option to the current option of limiting visibility to specific time ranges. In other words, you could limit visibility based on position and time separately.


Hi John
correct, provide separate options for time and for hemispheric visibility.

When I say about only drawing VGP ellipses and poles in either northern or southern hemisphere I don’t mean to show only those that plot in either one of the hemispheres, I mean to be able to force all poles to plot in one or other hemisphere i.e. to reverse the polarity in some cases. This is just an easy of visibility thing. Say one is concentrating on plate motions in a northern hemisphere view, then it would help to see how well poles that plot close to the south pole mtach either pole without having to move the view to a southern hemisphere perspective.