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I have a World View 3 image which is level Ortho Ready Standard Imagery (OR2A) processed and I wish to ascertain what this processing level means.

I need to work on surface reflectance and am aware that Digital Numbers (DNs) would need to be processed to Top of Atmosphere (ToA) radiance and then to surface reflectance.

However, being new to remote sensing the Digital Globe website information on what OR2a means has confused me (http://c-agg.org/cm_vault/files/docs/DigitalGlobe-Base-Product-FAQ.pdf) and I am left wondering - do I currently have data as DNs or as TOA reflectance?

Having checked, the pixel values for each band are integers ranging from 0 to 1227, so I do appear to have DNs!

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Yes - the regular OR2A data is delivered in Digital Numbers. If you want to test this, you could take a look at the values in your data - if all values you have are integers, chances are that you're looking at Digital Numbers, and if you have values between 0 and 1 in all bands, you're looking at reflectance (with the caveat that some data sources provide top of atmosphere reflectance rescaled into integers)

Just a note, most atmospheric correction algorithms rely on Top of Atmosphere radiance, and not reflectance is input.

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