How to create a threshold on a plot?

How do you create a binary array that tells you whether a (2D) plot is "yes" or "no" above a threshold of 0.5?

Answer 1

[KALYAN ACHARJYA]

Example:

data_2d=rand(1,20);  %Example 
threshold_val=0.5;
binary_array=data_2d>threshold_val  % This create a binary array based on threshold_val