In K2 overview map you can set clear map by reset buttons when use AJAX requests for filter data.
Here example, how configure K2 overview module
and where you can get name and classes
Form div you can find
You need form div to correct find buttons, because on page you can have a few buttons with the same name. In my case I have div ID, and use it for access
To find buttons
In my case I have only classes (submit and reset), and I use it for access