Initiatives: SPOT 5
SPOT 5 Further Information
The SPOT 5 satellite completes a circular orbit of the earth at an altitude of 822 km (measured at the equator) every 26 days. The orbit is near-polar to allow images to be acquired of any point on the earth’s surface, and sun-synchronous so that illumination conditions are as constant as possible. The satellite has several different sensors of varying capabilities, and is able to capture images of the same point on the earth (at slightly different viewing angles) every two to three days, depending on latitude.
Basic characteristics of the SPOT 5 satellite and its sensors are summarized in the following table.
SPOT 5 Orbit
| Type | Sun-Synchronous, 10:30 am (local solar time) descending node crossing |
| Altitude | 832 km |
| Inclination | 98.7 deg |
| Period | 101 min |
| Repeat Cycle | 26 days |
| Off-Nadir Revisit | 2 to 3 days |
Sensor Characteristics
| Swath Width | 60 km |
| Metric Accuracy | 30 m planimetric |
| Radiometric Digitization | 8 bits |
| Spectral Bands | Wavelength (µm) | Resolution |
| 1 (green) | 0.50 - 0.59 | 10 m |
| 2 (red) | 0.61 - 0.68 | 10 m |
| 3 (NIR) | 0.79 - 0.89 | 10 m |
| 4 (SWIR) | 1.58 - 1.75 | 20 m |
| Panchromatic | 0.49 – 0.69 | 5 m (2.5 m by interpolation) |
Further information on the SPOT program is provided in the press release 20th Anniversary of Launch of SPOT 1 Earth Observation Satellite (.pdf - 280 kb), or by visiting the links below.
SPOT 5 panchromatic images are fused with LANDSAT-5 images to add colour to the black and white image scenes. LANDSAT bands 1, 2, and 3 are all in the visible portion of the spectrum, while LANDSAT bands 4 and 5 are in the near-infrared and mid-infrared portions of the spectrum, respectively.
| Spectral Bands | Wavelength (µm) | Resolution |
| 1 | 0.45 – 0.52 | 30 m |
| 2 | 0.52 – 0.60 | 30 m |
| 3 | 0.63 – 0.69 | 30 m |
| 4 | 0.76 – 0.90 | 30 m |
| 5 | 1.55 – 1.75 | 30 m |
The following definitions are provided for some of the remote sensing and GIS terminology that appears in these pages.
Infrared spectrum - Electromagnetic radiation with wavelengths between about 0.7 to 1000 micrometers. Infrared waves are not visible to the human eye. Longer infrared waves are thermal infrared waves.
Image mosaic – An assemblage of photographs or other images whose edges have been cut and matched to form a continuous photographic representation of a portion of the Earth's surface.
Nadir – The point on the earth directly beneath a satellite, the opposite of zenith.
Orthophotograph - A photograph derived from a conventional perspective photograph by simple or differential rectification so that image displacements caused by camera tilt and relief of terrain are removed.
Orthorectify - The process undertaken to ensure that each image pixel is in its correct geographical position and to compensate for distortion caused by the terrain and the camera.
Panchromatic – Sensitive to all or most of the visible spectrum, between 0.4 and 0.7 micrometers.
Pixel – An abbreviation of picture element. The minimum size area on the ground sensed by a remote sensing device. The size varies depending on the type of sensor.
Spectral band - A slice of wavelengths from the electromagnetic spectrum.
Sun-synchronous orbit - An orbit in which a satellite is always in the same position with respect to the rotating Earth at the same time of day.
Visible spectrum - The electromagnetic
radiation that humans can see as colors. The visible spectrum is composed
of wavelengths between 0.4 to 0.7 micrometers.
For further information on remote sensing and GIS terminology, try searching the following on-line glossaries.
Canadian Centre for Remote Sensing
United States Geological Survey
The Association for Geographic Information (AGI) and University of Edinburgh GIS Dictionary
There are many interesting and varied resources available
on the World Wide Web. A few helpful links are provided below as a
starting point for those seeking further information about any of the
topics and concepts introduced on in this website.
Provincial government links
Ministry of Forests and Range, Forest Stewardship Division, Remote sensing and Geomatics
BC
Albers map projection
Base Map Online Store
Image file formats
Remote sensing
Remote Sensing Tutorial, from NASA/Goddard Space Flight Center
Remote Sensing Tutorial, from Centre for Remote Imaging, Sensing and Processing, National University of Singapore
Canadian Centre for Remote Sensing
United
States Geological Survey LANDSAT program
Cool stuff
