\nhorizon format: \n \nx1 h1 \nx2 h2 \nx3 h3 \nx4 h4 \n. \n. \n. \nxn hn \n \n \n \nxn> ... >x4 >x3 >x2>x1 \n \npicks (file) ascii file with two columns (x and h(x)) \nthe x values must be increasing order, \nyou can easily achieve that by doing: \n \nsort -k 1 unsorted_picks.txt > sorted_picks.txt \n \nstdin 2D file from which the axes will be read \nextend [false] Extends picks to the boundaries of the axis \nn Do not extend \ny Extend to boundary \n \ntmask [true] write a mask (1 if z>h(x)) \nfalse put a tic on the horizon \n \nabove [false] put 1 above the horizon \ntrue put 1 below the horizon \n \nntic [1] works with tmask=false; put 1 around ntic grid points \nabove and below the horizon. \n \nstdout It writes a file with the same dimensions as stdin \nwith a mask function, 1 below the horizon 0 above \n\n