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Let's take as an example of a spectroradiometer MODIS, and as an example of a multispectral sensor the Landsat8 (OLI). What is the difference between these two sensors?

Should we compare a spectroradiometer instead with a hyperspectral sensor since in the case of MODIS the number of bands is more important (36 bands).

  • converts invisible (to humans) light to visible Multispectral vs Hyperspectral Imagery Explained see gisgeography.com/… – Mapperz Jul 22 '15 at 16:10
  • @Mapperz thanks but I need to compare a spectroradiometer to a multispectral (or hyperspectral) sensor... I've already read that article btw. – Hakim Jul 22 '15 at 16:23
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According to NASA, a spectral radiometer is a multispectral sensor.

Spectroradiometer—A radiometer that measures the intensity of radiation in multiple wavelength bands (i.e., multispectral). Many times the bands are of high-spectral resolution, designed for remotely sensing specific geophysical parameters

Perhaps you're thinking of a spectrometer, which is slightly different, but similar

Spectrometer—A device that is designed to detect, measure, and analyze the spectral content of incident electromagnetic radiation. Conventional imaging spectrometers use gratings or prisms to disperse the radiation for spectral discrimination.

For the sake of being thorough,

Radiometer—An instrument that quantitatively measures the intensity of electromagnetic radiation in some bands within the spectrum. Usually, a radiometer is further identified by the portion of the spectrum it covers; for example, visible, infrared, or microwave.

And

Hyperspectral radiometer—An advanced multispectral sensor that detects hundreds of very narrow spectral bands throughout the visible, near-infrared, and mid-infrared portions of the electromagnetic spectrum. This sensor’s very high spectral resolution facilitates fine discrimination between different targets based on their spectral response in each of the narrow bands.

MODIS has an imaging spectroradiometer that measures 36 bands. Bands 1-19 are relatively wide, and imagery from these bands is considered multispectral. Bands 20-36 are much more fine, covering a nearly continuous spectral range, resulting in hyperspectral imagery.

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The Operational Land Imager (OLI) on Landsat 8 is also a multispectral sensor.

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  • First of all, thanks for the comprehensive list of definitions. No I meant a spectroradiometer (The S in MODIS). According to what you said, I understand that MODIS could be classified as a hyperspectral radiometer too, although since its bands are used to extract specific geophysical parameters (the water mask is an example) they call it a spectroradiometer maybe... – Hakim Jul 22 '15 at 18:18
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    @h4k1m You might take a look at gis.stackexchange.com/questions/101384 where the definition of 'hyperspectral' is discussed. While MODIS does have quite a few bands, I'm not sure I'd classify it as hyperspectral. Blake - your MODIS statement is a little confusing because you mention "along bands" and "from 250m to 1km" which is mixing spatial resolution with spectral resolution. You then go on to talk about OLI in terms of its spectral resolution. Spectral is given in nm/wavelength. But I think your answer is basically sound as summed in your first sentence. – Chris W Jul 22 '15 at 19:21
  • That's right, Chris. I've edited my answer to clarify that a little better. Feel free to add anything you think might help. – BlakeG Jul 22 '15 at 19:38
  • @ChrisW Sorry I meant multispectral. My question was whether MODIS which is a spectroradimeter could be considered a multispectral radiometer. According to what @BlakeG said indeed MODIS could be categorized as a multispectral radiometer. Thanks – Hakim Jul 22 '15 at 22:10
  • @ChrisW In the link you gave, should we replace radiometer with multispectral sensor and spectrometer with hyperspectral sensor?. – Hakim Jul 22 '15 at 22:27

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