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Tasseled Cap Transformation for Landsat 8

by cassie.tamblyn on ‎11-12-2015 01:22 PM - edited on ‎04-21-2016 05:50 AM by Technical Evangelist (6,328 Views)

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Description:

The Tasseled Cap Transformation is a technique commonly used in land cover mapping or other classification projects. It takes the linear combination of satellite imagery bands and a specialized coefficient matrix to create a n-band image with the first 3 bands containing the majority of the useful information, similar to Principal Component Analysis. The first three bands created are generally held to represent Brightness, Greenness and Wetness. The coefficient matrix, which is unique to each imaging sensor, is based on image statistics and empirical observations. The matrix[1] used in this model for the Landsat 8 OLI sensor is as follows (note that the first band of Landsat 8 OLI imagery, coastal aerosol, is effectively dropped): 

 

  LS 8 Band 1 LS 8 Band 2 LS 8 Band 3 LS 8 Band 4 LS 8 Band 5 LS 8 Band 6 LS 8 Band 7
Brightness 0.0000 0.3029 0.2786 0.4733 0.5599 0.5080 0.1872
Greenness 0.0000 -0.2941 -0.2430 -0.5424 0.7276 0.0713 -0.1608
Wetness 0.0000 0.1511 0.1973 0.3283 0.3407 -0.7117 -0.4559
TCT4 0.0000 -0.8239 0.0849 0.4396 -0.0580 0.2013 -0.2773
TCT5 0.0000 -0.3294 0.0557 0.1056 0.1855 -0.4349 0.8085
TCT6 0.0000 0.1079 -0.9023 0.4119 0.0575 -0.0259 0.0252

 

Other Landsat sensors can be transformed to Tasseled Cap from the Raster tab / Resolution group / Spectral pulldown.

 

Assumptions: The Landsat 8 OLI imagery should have been previously corrected to at-satellite reflectance values. This greatly increases the accuracy of the tasseled-cap transform. Information on this procedure can be found here: http://landsat.usgs.gov/Landsat8_Using_Product.php 

 

Below you can see how the resulting first 3 bands compare individually to the original image, which is displayed RGB to 4/3/2. 

First Band of TCT, Brightness, compared to the original image on right:
TCT1_compare.PNG
Second Band of TCT, Greenness, compared to the original image on right::
TCT2_compare.PNG
Third Band of TCT, Wetness, compared to the original image on right::
TCT3_compare.PNG

 

TasseledCapLandsat8-v15-1-1.gmdx
TasseledCapLandsat8-v15-1-1.PNG

 

  

Reference:

  1. Coefficient matrix derived from:

Muhammad Hasan Ali Baig, Lifu Zhang, Tong Shuai & Qingxi Tong (2014) 

Derivation of a tasselled cap transformation based on Landsat 8 at-satellite reflectance,
Remote Sensing Letters, 5:5, 423-431, DOI: 10.1080/2150704X.2014.915434

 

Comments
by cassie.tamblyn
on ‎01-07-2016 08:08 AM

Here's another relevant spatial recipe for Landsat 8 imagery from our partner Sterling Geo: "Calculate the Top of the Atmosphere Reflectance on Landsat 8 Images" found at http://www.sterlinggeo.com/spatial-modeler-library-index/ Thanks @JohnnieJ for this tip!

by LisaWins
on ‎02-25-2018 03:19 PM

Just a heads up, I was having trouble with this model, I then worked out that I needed to change the input raster type to a float rather than the default integer. My input was a float as this was the output of from the TOA conversion model (https://community.hexagongeospatial.com/t5/Spatial-Recipes/Landsat-8-Top-of-Atmosphere-Reflectance-C...)

tct input.PNG

by Technical Evangelist
on ‎02-28-2018 01:28 PM

Thanks Lisa,

 

I'm not sure why the original author hardwired the Raster Input operator to set the raster steam to Integer. If your input data happens to be Reflectance values that are still in the 0 - 1 floating point range, they'll get truncated to 0s or 1s. They may have set it this way because a common practice for Reflectance data is to multiply up by 10,000 or 20,000 and truncate to 16-bit integer to save a bit of disk space. If the input had been left its default "Native" setting it should work with both Float and Integer style Reflectance inputs. 

 

I'll fix the model tomorrow and re-post a new version to the original article.

 

Thanks  for pointing this out!

 

Cheers

by betitonice
3 weeks ago

Hi, sorry I can´t  open the link:  http://www.sterlinggeo.com/spatial-modeler-library-index/ 

is there another way?

 

TIA

 

by Technical Evangelist
3 weeks ago

Sure - just use the Download Model link at the top of the article (you will need to be registered and logged in to do so).

 

Cheers

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