Building Remotely Sensed Visions

The work explores the new European borders from two radically different points of view: the human and the machine. While the first is close to the scene or immersed in it, possessing a direct interaction with the represented reality, the second is derived using data collected by automatic sensors placed on satellite platforms (Landsat ETM+ 7), orbiting with a polar, sun-synchronous orbit at 705,000 meters of altitude. Consequently, the data is collected automatically from far away¿remotely sensed¿and without any interaction between the sensor, or who is pointing the sensor, and the recorded reality. The satellite sensor collects information about the quantity of electromagnetic energy emitted by the sun and then reflected, or directly emitted by each point of the scanned terrestrial surface. Electromagnetic energy means vibrating energy; the information on the quantity of energy collected by the satellite sensor is then subdivided by ¿type¿ of energy, using as a criterion the frequency of vibration. The sensor exploited in this work subdivides the energy in seven parts or ¿bands,¿ from the highest to the slowest vibration frequency (also called ¿spectral¿ information); we have the blue, green, and red portionparts of the visible spectrum, and then four bands in the infrared portionpart, until the slow vibration of the last infrared band, measuring the thermal energy emitted by the ground. It is important to understand that the whole system mentioned above, composed of orbiting satellite platform, sensor for data collection, transmission of data to the ground stations, and data storage and retrieval, can be considered almost automatic. Very little human intervention is needed during the normal operating conditions of this system, and human decision is required (almost) only in case of unexpected events producing failures in some of the system components. In brief, we have a remote, automatic machine, flying in space and sensing the ground surface, registering and storing the data on the reflected/emitted quantity of energy subdivided by vibration frequency. This data registration activity is automatic and completely indifferent to the scene registered. The data collected by the sensor forms a kind of stripe or scan following the trace of the satellite orbit on the ground, and then we can then mosaic these stripes and make a seamless representation of the terrestrial surface. This is what we call ¿remote sensing data,¿ and it is the raw material used in the present work.

PESARESI Martino; 

2009-12-02

Lars Muller

JRC55891

978-3-03778-176-0,