modify the color and legend in frequency analysis

[linyuelegant]

Hi everyone,

I am new to HYSPLIT back-trajectory analysis, and I have a question that needs your help.
I am just trying to make the frequency plot of trajectories. However, I find the frequency and its legends are only classified into 4 categories, > 100%, >10%, >1% and >0.1. How I can modify the gradient of frequency into like >50%, >40%, >30%, >20%, >10%, >5%, >3% ... with setting the colors I prefer for each category, e.g., from dark purple, to light blue?
I tried to open the *.ps file with notepad, and searched the lines where gradients, legends and colors are described and modify them. However, I am still not able to achieve the modification. Could you send me your quick guidance on doing this? Thanks!

-Zh