Topographic mapping from space

Topographic mapping from space
K. Jacobsen*, G. Buyuksalih**

*Institute of Photogrammetry and Geoinformation
Leibniz University Hannover
jacobsen@ipi.uni-hannover.de
** BIMTAS, Tophanelioglu Cad. ISKI Hizmet Binasi No:62 K.3-4
34460 Altunizade-Istanbul, Turkey
gb@bimtas.com.tr /

KEY WORDS: IKONOS, QuickBird, OrbView-3, mapping, high resolution, information contents, panchromatic, pan-sharpened

ABSTRACT:
Mapping today is a data acquisition for geographic information systems (GIS). Actual GIS information is required for any project planning. Especially in developing countries often no actual information is available. The data acquisition can be based on aerial, but also on space images for image scales up to 1:20 000 or for topographic maps with a scale 1:5000 or smaller. Sometimes aerial images are not available or even classified and photogrammetric image flights may be expensive and time consuming if no aerial survey craft is stationed in the country. So the use of space images for mapping often is an economic solution.
The ground sampling distance (GSD) has been shown as the key factor for object identification. In addition the object contrast, atmospheric condition, sun elevation and azimuth, spectral range and multispectral information plays a role. With WorldView-1 a GSD of 45cm is available, distributed with 50cm GSD, corresponding to medium aerial photo scale. But also with QuickBird (62cm GSD), IKONOS (82cm / 1n GSD) and OrbView-3 (1m GSD) as well as with the other new very high resolution optical space imagery a topographic mapping is possible. The results of mapping, using QuickBird, IKONOS and OrbView-3 images, are compared with large scale topographic maps. The influence of pan-sharpening against panchromatic images is shown.