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Remote sensing for Earth observation. Dr Nigel Trodd Coventry University. What is remote sensing?. remote sensing has been described as the means of sensing or measuring things (characteristics) without coming into direct contact with the object or phenomenon. What is Earth observation?.
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Remote sensing for Earth observation Dr Nigel Trodd Coventry University
What is remote sensing? remote sensing has been described as the means of sensing or measuring things (characteristics) without coming into direct contact with the object or phenomenon
What is Earth observation? observing our planet is a pre-requisite to a better understanding of its changes and the natural and anthropogenic processes that cause those changes
Aim & objectives • To understand remote sensing as a source of geodata for mapping & monitoring the Earth • Examine the role of remote sensing for Earth observation • Exemplify aspects of the geodata stream
What are the principles of remote sensing? • Source of electromagnetic radiation • Interaction with target • Measurement by sensor mounted on platform
EMR sources • Active remote sensing • Artificial source of EMR • Radar • Lidar • Passive remote sensing • Natural source of EMR • Sun (primary source for optical RS) • EMR emitted from Earth surface
What GI can be generated? • Extracting features e.g. buildings, roads • Land cover / land use classification • Estimation of biophysical properties e.g. biomass, ice-thaw
What preparation is necessary? • Cosmetic infilling of saturated pixels & drop-outs • Radiometric balancing (destriping) & sensor calibration • Atmospheric correction
How do you integrate images into a spatial database? • Georeferencing • Plane projection • Local datum & coordinate system • Co-registration • Rubber-sheet transformation • Nearest neighbour resampling
Orthorectification • Topography • DN • pixel geometry • foreshortening
Summary & conclusions Remote sensing generates • 2D & 2.5D GI products … at local to global scales using optical & microwave EMR • Images for Earth observation require • error detection & elimination • calibration & georegistration