Can you fix the area of the squares in Automagic heatmap

Hi,

I hav recently discovered Lookers Automagic heatmaps visualization. I can see that the squares change in size as you zoom in or out of the map. Do stop it from doing so I turned off the zoom option, but now the issue is that I want the area of the squares to be a fixed area of 5km^2. Is there a way to do this in Looker.

Thanks.