Clustered Regions by Each Neuron in Self Organizing Map (SOM) I was given a question about SOM. 

There is a SOM which have 4x4 neurons and each neuron's x1 and x2 values (coordinates) given. Also neighborhood function and weight update rule given. How can i find and show the regions which are clustered by each neuron?

Thanks for answers.

Regards...
When clustering an input, one should calculate the Euclidean distance to all neurons, then the input is assign to the cluster of the nearest neuron. 

In other words, for an input $v$ and a set of neurons $N$ (in your case $|N| = 16$ ) the cluster is:

$\text{Cluster}(v)=\arg \min_{i\in A}(||w_i-v||_2)$