Fig. 2
From: Mapping areas of spatial-temporal overlap from wildlife tracking data
a The accessibility space (G τ ) of an animal at time τ (i < τ < i + 1), where movement begins at known fix location a i and ends at known fix location a i+1 , is the intersection of the forward disc (D i,τ ) and past disc (D i+1,τ ). The union of the G τ , for all τ, is then the PPA; which by definition is an ellipse. b The joint accessibility space (G AB τ ) of two animals (A and B) at time τ (i, j < τ < i + 1, j + 1),, where movement begins at known fixes a i , b j , and ends at known fixes a i+1 , bj+1 respectively, is the intersection of G A τ and G B τ