1 Grid Shift File Formats
2 =======================
8 First line: comment, at most 80 characters in length.
12 <grid_size_x> <grid_size_y> <ignore> <lowleft_longitude> <resolution_longitude>
13 <lowleft_latitude> <resolution_latitude>
15 Angles are in decimal degrees.
20 <line_no>: <x_shift> <y_shift> *
22 The <line_no> is zero based, and will vary from 0 to <grid_size_y>-1. The
23 number of x/y shift pairs will match <grid_size_x>. Grid lines can be
24 split over multiple physical text lines. Use the colon to identify starts
25 of new grid lines. The shift values are in millionths of a secondc of arc.
28 For example, from MD.lla:
31 25 17 1 -80.00000 .25000 37.00000 .25000
32 0: 5107 -2502 -700 496 -656 468 -587 418 -481 347 -325 256 -111 152 166 50
33 493 -37 854 -96 1221 -118 1568 -125 1953 -143 2433 -195 2464 -281 2529 -395
34 1987 -729 447 -916 -3011 -1181 -5559 -406 -6094 541 -5714 1110 -5247 1289
36 1: 4757 -1695 -644 429 -627 411 -602 368 -555 299 -470 206 -328 96 -125 -15
37 126 -105 391 -146 634 -120 762 -58 911 -13 1583 -8 1049 -28 1451 123 1377 -464
38 907 -603 -4056 -1955 -6769 -485 -5797 929 -4254 1413 -3251 1295 -2871 993
42 The grid is 25x7, and covers the region with a lower left corner of
43 80d00'W 37d00'N and an upper right corner of 73d45'W 43d15'N.