IKONOS

[This page is under construction]

IKONOS is a commercial earth observation satellite. Details about the sensor in Digital Globe's IKONOS Data Sheet

Availability (Sample Data)

• Search for commercial satellite image providers in the internet.
• The Global Land Cover Facility (GLCF) provides four openly available IKONOS scenes of western Sichuan.

Pre-Processing Overview

Tyipically, multispectral data are converted into Reflectance before they are subjected in multispectral analysis techniques (image interpretation, band arithmetic, vegetation indices, matrix transformations, etc.). As with remotely sensed data acquired by other sensors, IKONOS raw image digital numbers (DNs) can be converted to physical quantities such as at-sensor Radiance or Reflectance. The latter can be differentiated in Top of Atmosphere Reflectance (ToAR) which does not account for atmospheric effects (absorption or scattering) and in Top of Canopy Reflectance (ToCR) which introduces a "correction" for atmospheric effects.

Converting to Top of Atmosphere Reflectance, also referred to as Planetary Reflectance, can be done by using the following equation:

Failed to parse (syntax error): {\displaystyle \rho_p = \pi * L\lambda * d^2 / ESUN\lambda * cos(θ_S)}

where:

• $\rho$ - Unitless Planetary Reflectance
• $\pi$ - mathematical constant (3.14159265358)
• $L\lambda$ spectral Radiance at the sensor's aperture, from equation... ToADD
• $d$ - Earth-Sun distance in astronomical units, interpolated values
• $Esun$ - Mean solar exoatmospheric irradiance(s) (W/m2/μm), interpolated values
• Failed to parse (syntax error): {\displaystyle cos(θ_s)} - Solar zenith angle, from the image acquisition's metadata

Modules overview

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Pre-Processing

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Importing data

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Color composites

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Pan Sharpening

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Calculate Planetary Reflectance

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References / Sources

• http://www.apollomapping.com/wp-content/user_uploads/2011/09/IKONOS_Esun_Calculations.pdf
• http://web.unicen.edu.ar/crecic/docs/radrefl.pdf
• Some short presentation about the DN to Reflectance conevrsion: Calibrated Landsat Digital Number (DN) to Top of Atmosphere (TOA) Reflectance Conversion, by Richard Irish

See also

• GRASS-Wiki page about Image Processing

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Atmospheric correction

See Atmospheric correction

IKONOS Image classification

See Image classification