This product survey provides the main characteristics of today's high-resolution imagery acquired from orbiting platforms and suited for mapping purposes. The survey includes both passive optical and active radar sensors.

By Mathias Lemmens, editor-in-chief, GIM International 

All satellites listed have a global coverage and all producers do deliver the products themselves to customers while most of them also make use of a global dealer network; only ImageSat and Kompsat 2 do not. Kompsat 2, also referred to as Arirang-2 by South Korea, has been developed by KARI (Korea Aerospace Research Institute) to continue the observation program of the KOMPSAT-1 mission.

The quality of satellite images depends on the level of post-processing. All providers carry out corrections on radiometry and geometry distortions introduced by the sensor system itself prior to delivery of the images to customers. However, the geometric quality of satellite imagery depends largely upon the use of additional information, in particular Ground Control Points (GCP) and Digital Elevation Models (DEM). Most providers deliver products on several levels of accuracy: raw imagery, geo-referenced imagery (using GCP) and ortho-rectified imagery, using DEM. Of course, the quality of used GCPs and DEM will affect the final quality of the satellite imagery and products derived from them.

One system still being in the process of development is part of the survey: WorldView-2. This system is anticipated to be launched in mid-2009. Operating at an altitude of 770km it will have an average revisit time of 1 day and be capable of collecting up to 975,000km² per day of half-meter panchromatic resolution and 1.8-meter multispectral resolution. No feedback on the questionnaire was received on the products of Spot Image. However, the features of SPOT 5/ HRS, SPOT 5/ HRG, SPOT 4/ HRV and Formosat-2 can be found in the Product Survey listed in the April 2006 issue. GeoEye is represented here with Ikonos. For the features of OrbView-2 and OrbView-3 refer again to the columns of the April 2006 issue. In the same columns it was announced that GeoEye-1, which will be able to collect images at 0.41-meter panchromatic (black & white) and 1.65-meter multispectral resolution, would be launched in 2007. The current launch date is scheduled for 22^nd August 2008.