5 votes
Accepted

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

You will want to use the *_sr_band1 to band7 data for your analyses as these are atmospherically corrected surface reflectance products (Figure 1). Only the Surface Reflectance data products and ...
Aaron's user avatar
  • 51.6k
4 votes
Accepted

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

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 ...
Mikkel Lydholm Rasmussen's user avatar
3 votes

Higher NDVI than SAVI

The formula for SAVI is: SAVI = (NIR - RED) / (NIR + RED + L) * (1 + L) The formula for NDVI is: NDVI = (NIR - RED) / (NIR + RED) From these formulas, it is clear that, depending on the values ...
Mikkel Lydholm Rasmussen's user avatar
2 votes

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

I have been using the the Semi automatic classification plugin of QGIS and I haven't had that problem. The plugin has a module for TOA correction.See the documentation
Peter M Macharia's user avatar
2 votes
Accepted

Are Landsat 8 data from ESPA corrected and calibrated?

Yes, these are the Level 2 data products, which are calibrated to surface reflectance. These are able to be used for further analysis directly. *_01_T1_sr_band1 to band7 refers to the surface ...
Aaron's user avatar
  • 51.6k
2 votes

GEE Python API: Mapping a function across ee.List and ee,ImageCollection

In general, yes, if you have a missing method like 'get', you likely need to write a cast inside the mapped function. However, there are bigger problems here. mat.map(perturb_image): given that mat ...
Kevin Reid's user avatar
  • 10.3k
2 votes
Accepted

Radiometric calibration of WorldView-2 imagery using ArcGIS Pro

Yes. Your understanding of the formula is correct. TOA_radiance = DN * absCalFactor / effectiveBandwidth This is the formula that you need. However, as you likely already know, your example value of ...
Mikkel Lydholm Rasmussen's user avatar
2 votes

Converting Landsat8 DN to TOA reflectance using GEE manually

May I ask, why are you going about it this way instead of using the built-in function for this purpose: ee.Algorithms.Landsat.TOA(input) ? Have a look at the documentation, but I suspect this might be ...
Pictory's user avatar
  • 169
2 votes

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

As the error message suggests, the ee.Algorithms.Landsat.TOA() expects an image, not image collection. If you want to apply this method to images within image collection - map a function, see https://...
Gennadii Donchyts's user avatar
2 votes

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

In most processing chains, orthorectification or reprojection is performed as late as possible in the workflow, to avoid altering the spatial relationships between neighbouring pixels. In your case, ...
Benjamin's user avatar
  • 911
1 vote

Radiance and Raw Image difference after Radiometric calibration

The raw image is the image as it is captured by the sensor. What you have after the radiometric correction is a conversion of the raw values (also called digit number) into a physical value (the ...
radouxju's user avatar
  • 49.6k
1 vote
Accepted

Radiometric, reflectance and atmospheric correction for Landsat 8 image

For radiometric corrections, you can use the surface reflectance data which can be ordered through EarthExplorer.Recently the USGS has developed software to apply calibration and atmospheric ...
Maxima's user avatar
  • 1,701
1 vote
Accepted

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

It depends entirely on what the atmospheric conditions are in your area, and on what degree of bias you are prepared to accept. As you are using two dates of imagery this becomes more important. An ...
Tom Higginbottom's user avatar
1 vote

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

I could not use SACRS2 for LISS3 images. The results are not good. I also made some tests and I found that the approach using the formula Lrad = (DN / MaxGray) * (Lmax - Lmin) + Lmin, as some people ...
Bindini's user avatar
  • 419
1 vote

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

They are not using uniform units. The first is using mW (miliwatts) for power and cm (centimeters) for wavelength, and the latter W (watts) for power and um (micrometers) for wavelength. You can ...
Benjamin's user avatar
  • 911

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