Cartographic Feature Extraction

Of all tasks in photogrammetry the extraction of cartographic features is the most time consuming. Since the introduction of digital photogrammetry much attention therefore has been paid to the development of tools for a more efficient acquisition of cartographic features. Fully automatic acquisition of features like roads and buildings, however, appears to be very difficult and may even be impossible. The extraction of cartographic features from digital aerial imagery requires interpretation of this imagery. The knowledge one needs about the topographic objects and their appearances in aerial images in order to recognise these objects and extract the relevant object outlines is difficult to model and to implement in computer algorithms. Therefore, only limited success has been obtain in developing automatic cartographic feature extraction procedures. Human operators appear to be indispensable for a reliable interpretation of aerial images.