title: Zooming in using D3
body: <p>How would I zoom in to a certain point on an svg at a certain point and then zoom out to the whole svg. There are only two states, I don't require mouse scroll zoom or a zoom in, zoom out button. </p>
  
  <p>I've looked up and found .zoom in d3 documentation, but am unsure of how to apply in my circumstances. I've only seen scroll zooms that are too complicated.</p>