i.tasscap(1grass)

✨ i.tasscap ✨

okay bestie, welcome to i.tasscap, a GRASS User's Manual page 💖 this one's a whole ~transformation~ moment and I'm obsessed, let's get into it 🦋

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🌸 NAME 🌸

i.tasscap — performs Tasseled Cap (Kauth Thomas) transformation. yep, that's the whole name, no cap 💅

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🎀 KEYWORDS 🎀

imagery, transformation, Landsat, MODIS, Worldview, Sentinel, Tasseled Cap transformation ✨

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🦋 SYNOPSIS 🦋

i.tasscap
i.tasscap --help
i.tasscap input=name[,name,...] output=basename sensor=string
[--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

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💜 Flags:

• --overwrite — lets output files overwrite stuff that's already there, no questions asked 👀
• --help — prints the usage summary, your little cheat sheet 🫶
• --verbose — verbose module output, it just talks more, iconic
• --quiet — quiet module output, the opposite vibe, shhh 🤫
• --ui — forces a GUI dialog to pop up, fancy

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💖 Parameters:

• input=name[,name,...] [required] — the bands, and which ones count depends on your sensor 🛰️:
  • for Landsat4-7: bands 1, 2, 3, 4, 5, 7
  • for Landsat8: bands 2, 3, 4, 5, 6, 7
  • for MODIS: bands 1, 2, 3, 4, 5, 6, 7
  • for Sentinel-2: bands 1 to 12, 8A
  • for Worldview-2: bands 1, 2, 3, 4, 5, 6, 7, 8
• output=basename [required] — basename for output raster map(s). like, the name for the output basename raster map(s) 💅
• sensor=string [required] — satellite sensor 🔭
  • Options: landsat4_tm, landsat5_tm, landsat7_etm, landsat8_oli, modis, sentinel2, worldview2

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🌈 DESCRIPTION 🌈

so i.tasscap calculates the Tasseled Cap (Kauth Thomas, TC) transformation for Landsat TM data (TM4, TM5, ETM7), MODIS and Sentinel-2 data. and the way that the tasseled cap transformation works is literally a compression method — it squeezes multiple spectral data down into a few bands 🫶 the method was originally developed for understanding important phenomena of crop development in spectral space (Kauth and Thomas, 1976). periodt, that's the origin story 🌱

Tasseled cap coefficients for Landsat 7 ETM+ are at-satellite reflectance values (C. Huang et al., 2001), and the conversion can be achieved with i.landsat.toar. noted bestie 📝

The following tasseled cap components are generated, and yes they're giving main character energy:

• tasscap.1: corresponds to brightness,
• tasscap.2: corresponds to greenness,
• tasscap.3: corresponds to wetness,
• tasscap.4: corresponds to atmospheric haze (only selected sensors: Landsat 5, 7, 8). so if you're not on those, no haze band for you, sorry not sorry 🙈

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⭐ EXAMPLE ⭐

Calculation of TC maps from North Carolina Landsat 7 ETM scene, ok here we go:

# See manual page of i.landsat.toar for pre-processing
g.region raster=lsat7_2002_toar.1 -p
i.tasscap sensor=landsat7_etm \
  input=lsat7_2002_toar.1,lsat7_2002_toar.2,lsat7_2002_toar.3,lsat7_2002_toar.4,lsat7_2002_toar.5,lsat7_2002_toar.7 \
  output=lsat7_2002_tasscap

Results 🎀:

• ’Brightness’ Tasseled Cap component 1 — and ’Greenness’ Tasseled Cap component 2
• ’Wetness’ Tasseled Cap component 3 — and ’Atmospheric haze’ Tasseled Cap component 4

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🧚 REFERENCES 🧚

• LANDSAT-4/LANDSAT-5: TC-factor changed to CRIST et al. 1986, Proc. IGARSS 1986, p.1467
• Crist, E. P., 1985, A TM tasseled cap equivalent transformation for reflectance factor data, Remote Sensing of Environment, 17: 301-306.
• LANDSAT-7: TASSCAP factors cited from: DERIVATION OF A TASSELED CAP TRANSFORMATION BASED ON LANDSAT 7 AT-SATELLITE REFLECTANCE. Chengquan Huang, Bruce Wylie, Limin Yang, Collin Homer and Gregory Zylstra Raytheon ITSS, USGS EROS Data Center Sioux Falls, SD 57198, USA (PDF). This is published as well in INT. J. OF RS, 2002, VOL 23, NO. 8, 1741-1748.
• MODIS Tasseled Cap coefficients - Ref: Lobser & Cohen (2007). MODIS tasseled cap: land cover characteristics expressed through transformed MODIS data. International Journal of Remote Sensing, Volume 28(22), Table 3
• Sentinel-2 Tasseled Cap coefficients - Ref: Nedkov, R. (2017). Orthogonal transformation of segmented images from the satellite Sentinel-2. Comptes rendus de l’Académie bulgare des sciences, 70:687-692.
• Yarbrough, L., Navulur, R., 2014, Presentation of the Kauth-Thomas transform for WorldView-2 reflectance data. Remote Sensing Letters. 5. DOI: 10.1080/2150704X.2014.885148.

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🍓 SEE ALSO 🍓

i.albedo, i.atcorr, i.landsat.toar, i.vi 🔥 go read those too, they're a vibe

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👑 AUTHORS 👑

• Dr. Agustin Lobo, original script, 1997
• Markus Neteler, ITC-irst, 2001
• Converted to Python by Glynn Clements
• Code improvements by Leonardo Perathoner
• Sentinel-2 support by Veronica Andreo
• Worldview-2 support by Markus Neteler

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💀 SOURCE CODE 💀

Available at: i.tasscap source code (history)

Latest change: Friday Jul 18 04:20:25 2025 in commit: 9c6890b933da3aad24b438f24dab0599d49edc2a

Main index | Imagery index | Topics index | Keywords index | Graphical index | Full index

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