Coronal holes are structures on the photosphere of the sun. They are in close relation to so-called geomagnetic storms, which have the potential of harming electronic devices in space and even on Earth. We present a method for extracting the coronal holes from magnetic field data of the Sun in an adaptive refinement manner. In contrast to previous methods our algorithm produces vector graphics representation instead of a texture which would show coarsely approximated coronal holes only. It takes advantage of the fact that the magnetic field of the Sun can be topologically divided into two parts which define the coronal hole boundaries.