Surfer Grid File Format

Golden Software Surfer ASCII Grid File Format (*.grd) example:

DSAA
257 257
5.67000000000000E+0005  5.77000000000000E+0005
6.21000000000000E+0006  6.22000000000000E+0006
-2.03093853524560E+0002  2.99665271953120E+0001
-90.5562486071858 -91.9770019939907 -93.4370976218987 -94.9176582413338 -96.8107561059735
-99.2457412347054 -102.100555111382 -105.05927200815 -107.450170173252 -108.397479844771
-108.006809781027 -106.952517601354 -105.649614366893 -104.213695019001 -102.692112629755
-101.114516990419 -99.5158982996779 -98.0913386982125 -97.2416961687762 -96.867635747979
-96.6288440424081 -96.4139655410412 -96.2387366687169 -96.1506385669487 -96.1889866969817
-96.3482126058032 -96.5828465379148 -96.8358291868982 -97.0430392786954 -97.1594814373822
-97.1602791675428 -97.0169815683541 -96.7126902739287 -96.2489776000008 -95.6594416328783
-94.9880962912902 -94.261664220667 -93.4897016947069 -92.7279351980489 -91.9532740429494
-91.1767254779275 -90.4266084443076 -89.731553749896 -89.120125489303 -88.683328917954
-88.356633504079 -88.167904067882 -88.023035728318 -87.838911878194 -87.552725344546
-87.266720734973.......
.
.
.
.

Line 1: File type indicator
Line 2: Number of columns and rows
Line 3: Min and max X
Line 4: Min and max Y
Line 5: Min and max Z (point elevation)
Line 6: First row of nodes in the grid
Line 7: Second row of nodes
.
.
.
.

See the Surfer documentation for a detailed description of the file format