This text file is essentially a copy of the most recently made ICQ shape file SHAPE.TXT that includes an additional column of sigma values.
SIGMA.TXT is made by densify and is located in the SHAPEFILES/ directory.
Here is a sample SIGMA.TXT file:
512 0.00810 0.19764 0.13333 0.29844E-01 0.00871 0.19742 0.13360 0.28206E-01 0.00932 0.19721 0.13386 0.27425E-01 0.00994 0.19700 0.13414 0.27743E-01 0.01055 0.19677 0.13441 0.28415E-01 0.01116 0.19655 0.13466 0.31917E-01 0.01177 0.19633 0.13493 0.31631E-01 0.01239 0.19615 0.13521 0.28469E-01 0.01300 0.19594 0.13549 0.28856E-01
The output values are:
Line 1 - Q (resolution). This gives the number of nodes for i and j. Multiple Q by 6 coordinate vector spaces to fill out the entire region.
Q*Q*6 is the total number of nodes, and line entries in this file.
A Q of 512 is the largest that we represent. It contains 1.5 million vertices and is 56 MB uncompressed.
Lines 2 and following - The location of a vertex in i, j, k space (Cartesian coordinates).
Column 1 - Position in x
Column 2 - Position in y
Column 3 - Position in z
Column 4 - Sigma values - JRW edit: densify.f doesn't read INIT_LITHOS.TXT, and multiplies a value by 1000 right before writing out SIGMA.TXT, so I'm fairly confident that the units are always meters.
(Compiled by TC) (Updated by JRW) CategoryFiles CategoryOutputFiles