Program sfpicks2rsf | Creates a mask from horizons:
[SYNOPSIS]
sfpicks2rsf < in.rsf > out.rsf ntic=5 tmask=y extend=n above=n picks=
[COMMENTS]

horizon format:

x1 h1
x2 h2
x3 h3
x4 h4
.
.
.
xn hn



xn> ... >x4 >x3 >x2>x1

picks (file)  ascii file with two columns (x and h(x))
the x values must be increasing order,
you can easily achieve that by doing:

sort -k 1  unsorted_picks.txt > sorted_picks.txt

stdin             2D file from which the axes will be read
extend [false]    Extends picks to the boundaries of the axis
n Do not extend
y Extend to boundary

tmask [true]     write a mask (1 if z>h(x))
false     put a tic on the horizon

above [false] put 1 above the horizon
true   put 1 below the horizon

ntic [1]     works with tmask=false; put 1 around ntic grid points
above and below the horizon.   

stdout       It writes a file with the same dimensions as stdin 
with a mask function, 1 below the horizon 0 above 

[PARAMETERS]
bool    | above | =n |  [y/n] | 	
bool    | extend | =n |  [y/n] | 	
int     | ntic | =5 |   | 	
string  | picks | = |   | 	parameters from input file
bool    | tmask | =y |  [y/n] | 	
[DIRECTORY]
user/ediazp
