Test Cases Poisson Values

In several plotting scripts, poisson data-type is a calculated value based on Vp and Vs values. The equation used is Poisson(Vs,Vp) = Vp/Vs except when Vs or Vp is 0 then the Poisson value is set to 0

Following is a series of plots of same parameters with different data-type,

./plot_horizontal_slice.py -b 33.35,-118 -u 34.35,-117 -e 1000 -d vs -c cvmh -a s -s 0.
01 -o hor_vs.png

./plot_horizontal_slice.py -b 33.35,-118 -u 34.35,-117 -e 1000 -d vp -c cvmh -a s -s 0.
01 -o hor_vp.png

./plot_horizontal_slice.py -b 33.35,-118 -u 34.35,-117 -e 1000 -d density -c cvmh -a s 
-s 0.01 -o hor_density.png

./plot_horizontal_slice.py -b 33.35,-118 -u 34.35,-117 -e 1000 -d poisson -c cvmh -a sd 
-s 0.01 -o hor_sd_poisson.png