Depending on the ordering, the input is as follows: (X, Y, elev, lon, lat) i. e. (3, 2, 1, 4, 5) specifies that X is in column 3 Y is in column2, elev in 1, lon in 4, and lat in 5 of the IBIS file. Default is (1, 2, 3, 4, 5).