= SIGMA.TXT =

== Description ==
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