Improving Automation in Map Updating Based on National Laser Scanning, Classification Trees, Object-Based Change Detection and 3D Object Reconstruction

Previously, several countries have performed countrywide laser scanning, but mainly for DTM purposes. This paper discusses the possibility to use countrywide collection of laser data, possibly multi-temporal laser data, for updating Topographic and forest databases, especially concerning the detection of the changed buildings or trees and reconstructing them from laser scanner data. Knowledge obtained in both the EuroSDR comparison of building extraction and EuroSDR/ISPRS test on tree extraction is applied in order to predict the obtainable quality. Some examples to use change detection are given. Rough concepts for implementation of the ALS surveys are depicted. The use of high-density cross-strips could be used for both strip adjustment and quality control. The intensity of the collected laser data is proposed to be calibrated. We also propose to use classification tree techniques together with existing methods in order to automatically classify laser point clouds.