GridMetric

The three distance metrics a Grid understands, each appropriate to a different movement model:

• 'manhattan' — sum of the axis deltas (|dx| + |dy|). The grid distance when movement is restricted to the four orthogonal directions. Produces diamond-shaped regions.
• 'chebyshev' — the larger axis delta (max(|dx|, |dy|)). The grid distance when diagonal movement is free. Produces square regions.
• 'euclidean' — straight-line distance (hypot(dx, dy)). Produces circular regions; useful for blast radii and falloff rather than step counts.