should not show barbs for NA velocities

[dankelley]

Does the barb plotting handle NA values. There are some grid values I set NA so they will not be plotted. These are just not plotted with the mapDirectionField(), which is what I want.

Originally posted by @mdupilka in #1 (comment)

[dankelley]

@mdupilka -- this topic was misplaced in #1 before, so I moved it here. As the new reporter, I will also be the one to close the issue, but I have named you in this comment so you'll see progress.

[dankelley]

Solved in commit 548c188