As my harddisk of my macbook was getting full, I needed something to select what files I wanted to remove. Following the classical 80/20 rule, a small number of files take a lot of place. The trouble is to find them. On pc, I used SequoiaView. Luckily, programs that generate tree maps also exist for the mac. First, I tried Disk Inventory X, a GPL program. It generates the treemaps, but does it very slowly. I looked a bit further and found GrandPerspective (also free software). That tool performed like I was used from SequoiaView.
Cast for two