What Are Uses of Reflectance Curves?

Defining Compounds

• The essential use of reflectance curves is to identify specific compounds based on how they reflect light. Minerals, rocks and regoliths have specific, known reflectance curves that serve as a kind of signature. Quartz and topaz, for example, each have their own signature reflectance curve. Scientists can observe an object, plot its reflectance curve and identify it based on matching it to the reflectance curve of a known substance.

Land Cover and Land Use Maps

• Land cover and land use maps show the types of substances that cover large areas of land such as asphalt, water, forests, sand and grass. These maps are often required for forestry, ecology and urban development projects. Reflectance curves are used to digitally differentiate these various land covers in photographs taken from remote sensors such as satellites and airplanes. A map is digitally created to enable people to easily visualize the various substances covering large land areas.

Soil Composition

• Reflectance curves of high resolution have been used to display conditions and characteristics of large surfaces of soil. Remote sensing has measured reflectance curves of soil in various regions to determine the quality, type and development stage of the soil. This has allowed scientists to build comprehensive pictures of the ecology and chemical makeup of large regions such as the eastern Mediterranean.

Astronomy

• Remote sensing from satellites has allowed astronomers to see reflectance curves of distant astronomical objects such as stars, asteroids and galaxies. This information enables astronomers to identify the chemical composition of distant objects without having to retrieve samples. Comprehensive understandings of various distant objects such as planets have been developed by matching their reflectance curves with those of known substances. All of the information we have for the most distant objects in the universe are the small amounts of light they emit or reflect. Reflectance curves allow astronomers to determine precise characteristics of those objects based on incredibly small amounts of light.