Visualize Hard Disk With GdMap

GdMap is a tool which allows to visualize disk space. Install it by typing in a terminal :

sudo apt-get install gdmap

To display directory structures cushion treemaps are used which visualize a complete folder or even the whole hard drive with one picture.

Start application by  Applications > Graphical Disk Map > File > Open ( I selected File System ) :

The larger a file is the larger is the rectangle which represents it. All files in one directory are painted within the rectangle of that directory.
The green/blue rectangle represents the directory /usr in the picture.

Links :
http://www.makeuseof.com/tag/how-to-analyze-your-disk-usage-pattern-in-linux/