title: Calculating area without overlap of polygon
body: <p>I have a question. I am trying to calculate the area of the following layer (see picture)
  <a href="https://i.stack.imgur.com/R0YQY.png" rel="nofollow noreferrer">intersect area</a></p>
  
  <p>I used the intersection tool to find the intersection between the layer of 4 overlapping buffers with another polygon (transformed from raster and therefore consists of many other polygons). This layers now consists of more than 200 polygons and most of them on top of each other. I actually want to calculate the 2D area of this layer, so I actually want to transform this layer of many polygons into one polygon so that you are able to calculate the area of this one polygon. My question is therefore, is there a possibility to transform this layer into polygons that are adjacent of each other and that there are no overlapping polygons anymore so I can calculate the area? Maybe there is another way to do this?</p>