EnvirSt 371 Midterm Exam

Remote Sensing

The science of deriving information about the Earth from satellite images and aerial photographs.

Aerial Photographs

Photographs taken from an airborne perspective, such as from a kite, plane, or balloon.

Satellite Imagery

Photos from orbiting satellites that cover large areas of Earth’s surface in multiple spectra with modest detail.

Landsat

The first earth-orbit satellite designed for observing land, providing spectral, spatial, and temporal data.

MSS

Multispectral Scanner System, the primary sensor for Landsat 1, producing high-quality multispectral imagery.

UAV

Unmanned aerial vehicles, used in aerial mapping and photography.

Photo-Interpretation

The field of analyzing photographs to derive information, precursor to remote sensing.

Photogrammetry

The practice of making accurate measurements from photographs.

Neighborhood Scale

High resolution remote sensing with 4m pixels, providing detailed images but covering a small area.

City Scale

Medium resolution remote sensing with 30m pixels.

Regional/Global Scale

Coarse resolution remote sensing with 500-1000m pixels, covering large areas with less detail.

Photographic Nadir

The intersection between the line from the ground nadir to the lens center on the actual image.

Active Remote Sensing

Detects radiation reflected by objects due to artificially generated energy sources, like radar.

Passive Remote Sensing

Detects radiation reflected by objects due to naturally generated energy sources, like the sun.

Chlorophyll Absorption

Chlorophyll preferentially absorbs blue and red light, reflecting green.

Albedo

The reflectance of surfaces, varying based on species and canopy structure.

NDVI

Normalized Difference Vegetation Index, a common index used in vegetation studies.

Radiometric Correction

Fixing sensor errors, atmospheric, or geometric distortions in images.

Orthorectification

A method for correcting images to ensure the scale is uniform across the image.

Supervised Classification

A method of classification where known training samples are used to categorize unknown data.

Unsupervised Classification

A method of classification that identifies patterns and clusters in data without prior knowledge.

Ground Control Station

A setup for managing and controlling UAV operations during remote sensing missions.

Atmospheric Transmittance

The amount of radiation that reaches the Earth's surface.

Rayleigh Scattering

A type of scattering that occurs when light interacts with very small particles in the atmosphere.

Pigments

Molecules that absorb radiation in visible wavelengths; their color reflects the wavelengths not absorbed.

Fluorescence

Emission of radiation at a different wavelength when an object is illuminated with radiation.

Thermal Infrared

Radiation that conveys temperature information about surfaces.

EM Radiation

Energy emitted by all objects, generated by changes in energy levels of electrons.

Spectral Sensitivity

The ability of a sensor to detect various wavelengths of EM radiation.

Temporal Resolution

The frequency at which data is collected over time.