The most common characterization of different remote sensing (RS) satellite imaging systems results from the systems diverse spatial, temporal and spectral resolutions.
The spatial resolution specifies the pixel size of satellite images covering the earth surface.
High spatial resolution: 0.6 – 4 m
Medium spatial resolution: 4 – 30 m
Low spatial resolution: 30 – > 1000 m
The temporal resolution specifies the revisiting frequency of a satellite sensor for a specific location.
IKONOS Satellite Temporal Resolution
High temporal resolution: < 24 hours – 3 days
Medium temporal resolution: 4 – 16 days
Low temporal resolution: > 16 days
In the first instance, a sensor’s spectral resolution specifies the number of spectral bands in which the sensor can collect reflected radiance. But the number of bands is not the only important aspect of spectral resolution. The position of bands in the electromagnetic spectrum is important, too.
High spectral resolution: – 220 bands
Medium spectral resolution: 3 – 15 bands
Low spectral resolution: – 3 bands
The different spatial, temporal and spectral resolutions are the limiting factor for the utilization of the RS data for different applications.
Unfortunately, because of technical constraints, satellite RS systems can only offer the following relationship between spatial and spectral resolution: a high spatial resolution is associated with a low spectral resolution and vice versa.
That means that a system with a high spectral resolution can only offer a medium or low spatial resolution.
Therefore, it is either necessary to find compromises between the different resolutions according to the individual application or to utilize alternative methods of data acquisition.
The trade-off may result in two different solutions:
- To lay emphasis upon the most important resolution, in direct dependency to the application, with the acceptance of low attendant resolutions at the same time, or
- To lay no emphasis on one specific resolution and at the same time the acceptance of a medium spectral, temporal and spatial resolution.
In most cases of the planning task, functions need regular local or regular regional data with a high spectral resolution as well as a medium or high spatial for planning functions, the resolution problem, i.e. a high spectral and ideally a high spatial resolution, is evident.
According to the above mentioned solutions for the resolution problem, the following sensors are recommended for the acquisition of RS data:
SPOT-5 neither spatial nor spectral resolution has to be as high as possible is the first of the high resolution satellites to truly balance large scene sizes with highly detailed imagery and a relatively high spatial resolution, with coverage of vast territories: scenes of 60 x 60 or 60 x 120 km.
Satellite Imaging Corporation – Providers of high resolution satellite images, aerial photos, GIS mapping and DEMs for industry mapping applications.