How to create continuous points and plot in quiver

Hello, I would like to seek your help. I had created discrete points and plot vector field by using the quiver function. Now, I would like to create continuous points which are in the same range (0 to 300), and the result of vector field should be the same as discrete points.

my code as below,

clear all; close all; clc
 
% discrete points
v = 0:25:300;
[x,y] = meshgrid(v);

z = -cos(x).*(-x.^2 - y.^2)*1e-4;
[px,py] = gradient(z);

figure(1)
quiver(x,y,px,py)
hold off