Finding Curl from a vector field picture

sjrrkb

1. The problem statement, all variables and given/known data
I need to analyze these pictures for my homework and find out the curl of the vector field at the point (red) on the picture.


2. Relevant equations

http://i1242.photobucket.com/albums/...6at61615PM.png

3. The attempt at a solution
basically I can calculate curl and divergence and evaluate them mathematically...but when it comes to analyzing a picture and determining the curl at a given point on a vector field I am totally lost. Any assistance....in the form of answers, places I can go to get help, or just suggestions would be appreciated.

lanedance

For the k component of curl, imagine a loop in the xy plane around the point in question, now imagine a line integral around the loop, what is the net result? Consider this for each axis and you should get close. You'll need to be careful with convention, to decide on +-.