14 votes
Accepted

Is the reflectance required to get the NDVI, for Landsat 8 images?

NDVI is defined for any two bands with near-infrared and infrared data (it is an empirical remote sensing index). As such, you can calculate it straight from the DNs. This is mostly OK if you are only ...
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  • 1,234
13 votes

Exported bands must have compatible data types; found inconsistent types: UInt16 and UInt32

If you have a look at Sentinel 2 bands you'll find that all bands are type unsigned int 16 except for QA20 that is unsigned int 32, that band is causing the issue. You can solve it in different ways,...
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11 votes
Accepted

Programmatically retrieving Landsat 8 Satellite Images?

I saw a blog post from developmentseed for their command line utility landsat-util. Power tools for Satellite Imagery The landsat-util can be forked from github and compiled from source unless your ...
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  • 9,921
11 votes
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Cloud mask for Landsat8 on Google Earth Engine

Please, read the related answer. Use the right parameters and always check metadata You're trying to filter with BQA band and in SR product, there is no BQA band, there is pixel_qa band instead. ...
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  • 11.8k
11 votes

Cloud mask for Landsat8 on Google Earth Engine

@Aldo's answer is the correct one, no doubt, but if you want to make the code shorter and you don't mind loosing the 'core' of cloud masking, you can use a module: var point = /* color: #98ff00 */ee....
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10 votes

Is it scientifically correct to pansharpen landsat reflectance product with pan band

Fundamentally the question here is "what does 'scientifically valid' mean". If you are looking to do spectral modelling on the data, then the answer is possibly different than if you are looking at ...
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9 votes

EVI and NDVI range value

You are right: the range of the NDVI is limited to values between -1 and 1 due to its' normalization properties. The negative limit of -1 will be reached if you encounter maximal reflectance (1) in ...
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  • 176
9 votes
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From where can I get Landsat 7 and Landsat 8 metadata files?

The USGS provides a tool for bulk downloading of Landsat Metadata: Landsat Bulk Metadata Service The MTL files will allways be distributed with the data if you download the scenes through USGS ...
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  • 9,410
8 votes
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Error installing landsat-util on Linux

gnutls.h which is required is missing from the filesystem even if you install libcurl4-gnutls-dev which supposedly has the headers files for curl. to correct for that error run: # apt-get install ...
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  • 11k
8 votes
Accepted

Counting number of pixel identified as water from a collection of landsat image using Google Earth Engine

It's going to be something like this: var landsat8= ee.ImageCollection('LANDSAT/LC8_L1T_TOA').filterBounds(geometry) var waterThreshold = 0; // water function: var waterfunction = function(image){ ...
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7 votes

Why does Landsat 8 panchromatic band NOT include the infrared?

Forgive me if this is too basic an answer: panchromatic and infrared are mutually exclusive. Panchromatic means all visible light, which is generally considered to range 0.4μm to 0.7μm in wavelength. ...
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  • 8,604
7 votes
Accepted

Landsat8 DN to TOA Reflectance (minus values)

One flaw in your approach. You don't need to go through DN to radiance. You can go straight to the DN to reflectance. Just stick to ((B1*0.00002)-0.1)/0.74457226676389733207607359928648.
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7 votes
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Why vegetation index, NDVI or SAVI is not working in the desert?

The sensitivity of the normalized difference vegetation index (NDVI) to the soil background and atmospheric effects has generated an increasing interest in the development of new indices. The NDVI ...
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  • 1,677
6 votes

Landsat Observation Zenith and Azimuth Angles

Satellite zenith angle Images from Landsat 1 - 7 are always nadir. In other words, their satellite zenith angle is close to 0°. Likewise, the _MTL.txt you posted corresponds to a Landsat 5 image, ...
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  • 800
6 votes
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How to use the same ROI for multiple LANDSAT images in ENVI?

ROIs in ENVI are stored in pixel-based co-ordinates, with no geographic information at all. The size of the image used to create the ROI is stored in the ROI file, and when you open the ROI list for ...
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  • 3,866
6 votes
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Viewing bands of landsat 8 images in QGIS for NDVI calculation?

You have downloaded the data and you can find it if you unpack the .tar.gz file using 7zip or similar software for unpacking files. The .tar.gz file is the fourth file from the top that can be seen in ...
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6 votes
Accepted

NDBI formula for Landsat 8

I am not 100% familiar with the NDBI Index, but found an article here: https://www.researchgate.net/publication/273886729_Built-up_area_extraction_using_Landsat_8_OLI_imagery Specifically on Page 14 ...
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  • 3,404
6 votes
Accepted

Exporting entire ImageCollection in Google Earth Engine using geetools for JavaScript or Python for Windows?

I am the author of both geetools (Python and JavaScript) The JavaScript repo is share with anyone can read so it should work, but anyhow you can click here to accept the repo, and then do: var batch = ...
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6 votes
Accepted

Smoothing/interpolating across images in an ImageCollection to remove missing data

You can replace the values using where(). // Replace masked pixels by the mean of the previous and next months // (otherwise, how to deal with the first images??) var replacedVals = composites.map(...
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  • 9,258
5 votes

Workflow of Processing Landsat data for landcover classification

Usually you start with cloud (and cloud shadow) removal then you run the classification. One of the best papers I know about cloud detection on Landsat is Zhu and Woodcock (2012)
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  • 48.6k
5 votes

how i calculate land surface temperature using landsat 8 in Envi 5.1

Step 1: Convert from digital numbers (DN) to radiance This is done by applying the multiplier and addition numbers as found in the metadata (.MTL) file. For the thermal bands (B10 and B11), the ...
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5 votes
Accepted

Clipping of a Raster changes Range of Cell Values

Your clipping fails because the raster has the odd nodata value of -3.4E+38. Unfortunately, you can not enter that value in the input form. So I suggest to use gdalwarp to change the nodata value and ...
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  • 74.9k
5 votes

Sun glints and landsat 8 surface reflectance product

The Landsat 8 Surface Reflectance products are not sunglint corrected , so if your application is going to be adversely impacted by the presence of sunglints, then you should implement a suitable ...
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5 votes
Accepted

Do clouds reflect NIR/Red bands

Yes, it affects the values of NDVI, and it may not give the desired results sometimes. Information from Wikipedia: Normalized Difference Vegetation Index provides some details about the effects of ...
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  • 36.2k
5 votes
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Atmospheric effects on extracting soil from BSI index?

Bare soil and urban areas are notoriously hard to segregate. Even with a perfect atmospheric correction, there will be relatively high confusion between the two, particularly when limited to ...
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  • 1,249
5 votes
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What are the necessary correction/calibration on Landsat 8 imagery for land cover classification?

You can perform a land cover classification on a single Landsat scene without performing spectral and radiometric corrections. You will only need to do those corrections if you're trying to apply ...
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  • 1,070
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 ...
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  • 50.2k
5 votes
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Do we get world grid with date and time of visit of Sentinel 1 and Sentinel 2?

About Tiles: There is a kml file provided by ESA that shows the location of each Tile. Overlay it with your study area and you will see which is your target tile. About acquisition: Acquisiton ...
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  • 1,058
5 votes
Accepted

How to add to the map all the images on a image collection with cloud pixels masked on Google Earth Engine?

The solution you have tried uses the image 'id' so you end up displaying the 'original' image in the collection. As an alternative, following what you said in the comment, you can use the .get() ...
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  • 515
4 votes

Programmatically retrieving Landsat 8 Satellite Images?

I intend to do the same so I start an Amazon EC-2 instance and install the Bulk Download on it. But as far as I know it's a graphical application and nothing in the doc Bulk Download Tutorial lets ...
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