Clickable Image map with global variable

Hello everyone,

I placed an image on my dashboard and I'm using the HTML map tag to click on a specific figure inside that image. Now I was able to get it running but I would like that when I press this figure, to set a global variable to a specific value in my flow like for example global.variable = machine1


<map name="robot">
  <area shape="rect" coords="350,150,500,300" alt="Machine 1" ng-click="send({topic: 'map', payload: 'machine1'})">
</map>

But I don't know how to do that.

I would appreciate any help.

Thanks