A single layer of an image created using a specific range of wavelengths. A color digital image is composed of three bands that record red, green, and blue wavelengths of light.
Glossary
Remote Sensing Resources > Glossary
Some of these terms have broader definitions than the one given. The definitions in this glossary are relevant to remote sensing applications. Some of these terms are defined in more detail in the Basic Concepts section of this site.
Remote Sensing Resources > Glossary
Some of these terms have broader definitions than the one given. The definitions in this glossary are relevant to remote sensing applications. Some of these terms are defined in more detail in the Basic Concepts section of this site.
Band
A single layer of an image created using a specific range of wavelengths. A color digital image is composed of three bands that record red, green, and blue wavelengths of light.
A single layer of an image created using a specific range of wavelengths. A color digital image is composed of three bands that record red, green, and blue wavelengths of light.
Channel
This is typically synonymous with "band". In the guides on this web site, however, we use the term "channel" to represent the different colors of light that are used to display an image on a computer screen.
This is typically synonymous with "band". In the guides on this web site, however, we use the term "channel" to represent the different colors of light that are used to display an image on a computer screen.
Hyperspectral
Many bands (often more than 100). Some hyperspectral sensors are capable of recording images with more than 200 bands and each band represents a specific (usually very narrow) portion of the electromagnetic spectrum.
Many bands (often more than 100). Some hyperspectral sensors are capable of recording images with more than 200 bands and each band represents a specific (usually very narrow) portion of the electromagnetic spectrum.
Open source software
Software that has the source code freely available and is licensed so that it can be freely distributed and modified as long as appropriate credit is provided to the developers. There are several licensing options for open source software but all of them follow these basic rules. More information about open source software is available at the Open Source Initiative web page (http://www.opensource.org/)
Software that has the source code freely available and is licensed so that it can be freely distributed and modified as long as appropriate credit is provided to the developers. There are several licensing options for open source software but all of them follow these basic rules. More information about open source software is available at the Open Source Initiative web page (http://www.opensource.org/)
Sensor
A device that is capable of recording the intensity of electromagnetic radiation. In remote sensing these devices typically record this information in images rather than from a single point.
A device that is capable of recording the intensity of electromagnetic radiation. In remote sensing these devices typically record this information in images rather than from a single point.
Pixel
An individual "picture element" from an image. When an image is magnified the individual pixels can be seen as a square or rectangular block in the image.
An individual "picture element" from an image. When an image is magnified the individual pixels can be seen as a square or rectangular block in the image.
Wavelength
Distance between two crests of a wave. In remote sensing electromagnetic waves are typically measured in nanometers, millimeters, and centimeters.
Distance between two crests of a wave. In remote sensing electromagnetic waves are typically measured in nanometers, millimeters, and centimeters.
Electromagnetic Spectrum
The range of wavelengths of electromagnetic radiation. Remote sensing applications typically use wavelengths that include the visible wavelengths (blue through red), the infrared, and microwave regions of the electromagnetic spectrum. The shorter wavelength ultraviolet, x-ray, and gamma rays are not typically used. The long wavelength radio waves are also not typically used.
The range of wavelengths of electromagnetic radiation. Remote sensing applications typically use wavelengths that include the visible wavelengths (blue through red), the infrared, and microwave regions of the electromagnetic spectrum. The shorter wavelength ultraviolet, x-ray, and gamma rays are not typically used. The long wavelength radio waves are also not typically used.
Radiation
Energy transferred as particles or waves through space or other media. In remote sensing radiation often comes from the sun although is can also come from the sensor as is often the case with LIDAR and RADAR sensors.
Energy transferred as particles or waves through space or other media. In remote sensing radiation often comes from the sun although is can also come from the sensor as is often the case with LIDAR and RADAR sensors.
Multispectral
Multiple bands with each band recording a different portion of the electromagnetic spectrum.
Multiple bands with each band recording a different portion of the electromagnetic spectrum.
Feature recognition
The ability to identify a feature on a digital image. In remote sensing this can refer to identifying man made features such as buildings or airplanes but it can also refer to natural features such as land cover or topographic features such as ridges and valleys.
The ability to identify a feature on a digital image. In remote sensing this can refer to identifying man made features such as buildings or airplanes but it can also refer to natural features such as land cover or topographic features such as ridges and valleys.
Classification
The process of identifying and labeling features on an image. Pixels are grouped into categories using manual or automated methods.
The process of identifying and labeling features on an image. Pixels are grouped into categories using manual or automated methods.
Resolution
The smallest detail visible in an image. Usually resolution refers to spatial resolution. The spatial resolution of an image is an indication of the size of a pixel in terms of ground dimensions. It is usually presented as a single value that represents the length of one side of a square. For example, a spatial resolution of 30 meters means that one pixel represents an area 30 meters by 30 meters on the ground. If the pixel is rectangular it will be represented by a height and width dimension (i.e., 56m x 79m).
The smallest detail visible in an image. Usually resolution refers to spatial resolution. The spatial resolution of an image is an indication of the size of a pixel in terms of ground dimensions. It is usually presented as a single value that represents the length of one side of a square. For example, a spatial resolution of 30 meters means that one pixel represents an area 30 meters by 30 meters on the ground. If the pixel is rectangular it will be represented by a height and width dimension (i.e., 56m x 79m).
Radiance
Measure of radiation energy. Radiance is usually measured in watts per unit solid angle area.
Measure of radiation energy. Radiance is usually measured in watts per unit solid angle area.
Reflectance
Ratio of the intensity of reflected radiation to that of incident radiation on a surface. Reflectance is expressed in percent and usually refers to a specific wavelength.
Ratio of the intensity of reflected radiation to that of incident radiation on a surface. Reflectance is expressed in percent and usually refers to a specific wavelength.
Spectral reflectance curve
A curve describing the reflectance values for a particular feature over a range of wavelengths. The x-axis is for wavelength and the y-axis is for reflectance. Different features have unique spectral reflectance curves. An example of difference spectra can be seen using the spectral curve interactive tool.
A curve describing the reflectance values for a particular feature over a range of wavelengths. The x-axis is for wavelength and the y-axis is for reflectance. Different features have unique spectral reflectance curves. An example of difference spectra can be seen using the spectral curve interactive tool.
