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Questions tagged [toa-calibration]

For questions related to calibration techniques for Time of Arrival (TOA) calculations for Radiolocation (the process of finding the location of something through the use of radio waves). This can also apply to Top of Atmosphere (ToA) reflectance.

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172 views

Radiometric, reflectance and atmospheric correction for Landsat 8 image

I am struggling with the pre-processing process for landsat8 imagery. I want to use some indices (e.g. NDVI, SAVI, EVI, NDMI) and create a land cover map at the end using ENVI and ArcGIS. As a ...
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1answer
264 views

Convert a collection of raw Landsat 8 scenes to top-of-atmosphere reflectance

This link , use ee.Algorithms.Landsat.TOA(input) to convert a raw Landsat scene to top-of-atmosphere reflectance (TOA). I am trying to convert a collection of raw Landsat 8 scenes (LANDSAT/LC8 ) to ...
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1answer
301 views

Are landsat 8 SR and TOA rasters calibrated/corrected data or the data to be used for calibration/correction?

I downloaded Landsat 8 Level-2 scenes from https://espa.cr.usgs.gov/ for land cover classification. Following are the product list in the package, cause I ticked Top of Atmosphere Reflectance (TOA), ...
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2answers
297 views

Are Landsat 8 data from ESPA corrected and calibrated?

I am trying to figure out Landsat 8 data corrections and calibrations. Actually, I don't really know how this can be done and which data needs what kind of correction and calibration for further ...
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1answer
57 views

GDAL deletes metedata file when creating GTiff

Reposting question explaining it better. I am doing TOA corrections on Landsat8 Images in Python(3.5) by reading all image_bands and after processing them creating new GTiff of those images with GDAL,...
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1answer
88 views

When calculating temperature from Landsat is it necessary to use TOA?

I'm attempting to calculate temperature from Landsat 5 and 8 thermal bands. I've already calculated NDVI, where the NDVI bands were corrected using dark object subtraction. I see that many people use ...
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1answer
434 views

How to convert the DN values of Resourcesat-2 LISS-3 images to Radiance?

Does somebody knows How to convert to Radiance the Resourcesat-2 LISS-3 images? I found a paper "Pre-flight Radiometric and Spectral Calibration of Resourcesat-2ALISS3* payload", where they ...
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1answer
457 views

WorldView 3 level OR2a processing - do I have data as DNs?

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 ...
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1answer
145 views

After doing TOA correction to a lansat 8 image band using raster calculator, the reflectance is slightly out of range. Why is that so?

the reflectance range was like for example 0.0023 to -1.02356 for some band and -0.0156 to 0.009. Why is this reflectance range slightly out of range? Isn't it should be in exactly in between 0 to 1. ...
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1answer
250 views

Higher NDVI than SAVI [duplicate]

I have calculated NDVI and SAVI for landsat-8 image. But I am getting higher value of NDVI than SAVI Can you tell me reason for this NDVI=0.46 SAVI=0.34 Specific band pixel values are toa b4- 0.130 ...
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1answer
552 views

Differences between mWm-2sr-1(cm-1)-1 and W/m^2 * sr * um

I'm confused about the use of this quantity. For example eumetsat on pag. 16 radiance is equal to: Physical Units = Cal_Offset + (Cal_Slope x Level 1.5 Pixel Count) expressed in mWm-2 sr-1 (cm-1)...
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1answer
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Is the reflectance required to get the NDVI, for Landsat 8 images?

I'm a beginner in satellite optical imagery. I have a landsat 8 image (11 bands downloaded from http://earthexplorer.usgs.gov/) for which I need to calculate the NDVI (Normalized Difference Vegetation ...
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2answers
3k views

Landsat8 DN to TOA Reflectance (minus values)

I'm learning how to perform atmospheric correction manually, hence not using the automated methods available in ENVI metadata (band 1) for my Landsat 8 scene is as follows; RADIANCE_MULT_BAND_1 = 1....
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1answer
338 views

Which preprocessing comes first for pansharpened imagery- atmospheric correction or orthorectification?

For pansharpened imagery, what preprocessing method to do first- is it atmospheric correction or orthorectification? From my readings, it seems the former but the rational polynomial coefficients or ...
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3answers
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Atmospheric correction for pansharpened imagery? [closed]

In converting DN values to radiance as well as reflectance, do we use the same equations in raw satellite imagery for pansharpened products? I saw this DigitalGlobe technical note for DN to radiance ...