Abstract
Landform skeleton are lines that indicate significant topographic features of the terrain. It is widely used in mapping and
surveying, hydrology simulation, topography representation and engineering designing. In order to derive the landform
skeleton, many kinds of data source have been used, including digitized contour lines, Grid-DEMs and TIN. As time
goes by, more and more unorganized points have been acquired, created, maintained and disseminated in many fields.
Those unorganized points are the most original and important information which is vital for mapping and surveying.
How to extract the feature lines from unorganized points has been the hot-pot in computer design and reverse-engineering.
Methods used to extract landform features in existence have shown dependence on data types and
thresholds more or less. In the paper, the view sheds principle used to extract the feature points has been put forward and
then those points have been organized into feature lines according to related rules. The result has shown that the view
sheds principle can extract the features and give the levels of feature points.
