Producing a building change map for urban management|
Teresa Santos, Sérgio Freire, Ana Fonseca, and José António Tenedório
The high rate of changes in cities requires the existence of matching geographic information in order to enable proper land monitoring and planning. When cartographic information exists, but is out-dated, a change detection procedure using recent geographic data can be applied for map updating. The aim of such an analysis is to highlight those areas where changes have most likely occurred.
The goal of this work is to present an object-oriented methodology that enables outdated large-scale cartography to be updated, using Very-High Resolution (VHR) imagery and Light Detection and Ranging (Lidar) data. The procedure is a two-step method. The remote sensing data is used to map the present land cover situation, and then, based on a change/no-change approach the land information is used for updating the large-scale cartography.
The result is an alarm system that indicates the location of potential changes in the built-up zones. However, in order to be a legally valid document, the mapped objects must comply with the technical specifications of the respective cartographic scale. This is not possible strictly based on an automatic methodology, and requires further human intervention. Therefore, the alarm layer can then be used by the municipal technical staff as the basis for manual editing, following the technical specifications indicated for the desired map scale.