How to avoid to plot the NAN value?

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.

then rearranging the above code I manage to plot that.

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???

Answer 1

[José-Luis]

Assuming all dimensions match:

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;

Then:

tempX = xarray(1:4:end);
tempY = yarray(1:4:end);
idx = ~isnan(XX_T) & ~isnan(YY_t);
quiver(tempX(idx),tempY(idx),XX_t(idx),YY_t(idx),'k','filled');

Answer 2

[Lorenzo]

If you plot:

        quiver(x,y,Dx,Dy);

you will see a arrow from the position (x,y) to the position (x+Dx,y+Dy)

If yout plot:

        quiver(x,y,NaN,NaN);

you will see a dot in the position (x,y)

If you plot:

        quiver(NaN,NaN,NaN,NaN);

you won't see anything

Set the positions to NaN