Visualization of the streamlines corresponding to a 2D vector field

Hi,

I have a vector field over a 2D domain and I would like to visualize some of its streamlines. My data are not distributed continuously throughout the domain but rather onto discrete points.

To be more specific, I have the following two arrays X(:,:) and Y(:,:) which define the x and y Cartesian coordinates of the points where I have the vector field data with components U(:,:) and V(:,:) respectively. However, I have not managed to visualize the streamlines of the field using the streamline function provided by MATLAB successfully so far.

Any hint or provided example will be highly appreciated,

Andreas