How can I plot the vector for specified node?

I am using following command

 quiver(xarray(1:4:end),yarray(1:4:end),DV_XX(1:4:end),DV_YY(1:4:end),1, 'k','filled');

which is plotting the vector for every node. I want to plot for every alternate node that means it will plot 1st node then do not plot arrow for 2nd node the again plot the arrow for 3 rd node.

Any idea how can I do that?

Answer 1

[Walter Roberson]

 XX_t = DV_XX(1:4:end);
 XX_t(2:2:end) = NaN;

and plot with XX_t instead of DV_XX(1:4:end)

[Tan Has]

THIS IS WORK FOR ME

XX_t = DV_XX(1:4:end);
      XX_t(3:3:end) = NaN;
      YY_t =DV_YY(1:4:end);
      YY_t(2:3:end) = NaN;
             quiver(xarray(1:4:end),yarray(1:4:end),XX_t,YY_t,1, 'k','filled');

BUT THE NAN VALUE IS PLOT AS A DOT IN THE FIGURE. I DON'T WANT TO SHOW THAT. HOW CAN I DO THAT.