correction lines

correction lines

Provisions in the public land survey system made to correct for the curvature of the earth; one cannot have perfect rectangles over a curved surface. Every fourth township line (24 miles apart) is used as a correction line on which the spaces between the east and west range lines are corrected to a full and proper 6 miles.The effect is that the grid lines do not match up until they meet at the principal meridian.

References in periodicals archive ?
It follows much the same trajectory correction lines as the Excalibur but it is anticipated that ranges of well over 80,000 metres will be achieved, thanks partially to rocket assistance.