Remote Sensing is defined as the ability to acquire information about an object without any physical contact with it.
Information about the object, in this case, is derived from the detection and measurement of the changes it imposes on the force fields surrounding it.
These force fields can be electromagnetic, acoustic or potential. Basically, Remote Sensing is conceived as a system for acquiring information about the terrestrial environment based on the systematic use of remote sensors.
Electromagnetic Energy
Electromagnetic Energy is the medium through which information is transmitted from the object to the sensor.
Information can be encoded in terms of the frequency, intensity and polarization of the electromagnetic wave.
As electromagnetic radiation propagates at the speed of light, the higher its frequency, the shorter its wavelength.
High-frequency, short-wavelength radiation has higher energy levels than low-frequency radiation, so the interactions between electromagnetic radiation and objects vary across the electromagnetic spectrum.
LANDSAT and SPOT
Among the techniques available for obtaining images, the best known is the use of passive sensors installed on satellites of the LANDSAT and SPOT series.
LANDSAT satellites orbit at an altitude of 705 km, passing over at least every 16 days, and cover an area of 185 km² in each scene. This satellite has a spatial resolution of 30 m (Landsat 5) and a resolution of 15 m (Landsat 7).
SPOT satellites are at an average altitude of 832 km and pass over the same scene daily. They have a panchromatic spatial resolution of 10 meters and multispectral resolution of 15 m.
Capabilities
The use of Satellite Imagery at ESTEIO spans more than 10 years across various services such as:
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Forest thematic mapping using Landsat images;
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Thematic mapping using Landsat images for environmental impact studies;
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Generation of image maps using Landsat images for updating conventional cartography and as a base layer for GIS;
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Generation of image maps using SPOT images, for the province of La Rioja in Argentina.
ESTEIO uses the specific Remote Sensing software ERMapper, which enables, among other tasks:
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Georeferencing of satellite images and digitized aerial photographs;
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Image rectification;
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Generation of image maps and orthoimages;
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Supervised and unsupervised classification for thematic mapping purposes;
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Radiometric treatment and image balancing;
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Automatic mosaicking and photo index preparation;
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Perspectives and three-dimensional models;
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Multi-layer terrain analysis;
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Fly-through;
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Hypsometric maps;
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Map preparation with the insertion and manipulation of vector files in various formats.