I1S1O1G2R1I1V4S1
12 points
ISOGRIVS is validvalid
ISOGRIV, a line drawn on a map such that all points have equal grid variation [n]
ISOGRIV, a map line indicating equal grid variation [n]
ISOGRIV, a line drawn on a map such that all points have equal grid variation [n]
ISOGRIV, a map line indicating equal grid variation [n]