i.tasscap(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 i.tasscap — the manual page but make it a group chat 💖

okay bestie, welcome to i.tasscap from the GRASS GIS User's Manual, section 1 (that's the user commands section, iykyk). this one is a whole vibe: it does the Tasseled Cap (Kauth Thomas) transformation. yes it's a real thing, yes it sounds like a laundry setting, no we will not be normal about it.

✨ NAME ✨

i.tasscap — performs Tasseled Cap (Kauth Thomas) transformation. that's it, that's the whole thing. slay. 💅

🏷️ KEYWORDS 🏷️

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

ngl that keyword list is giving "i contain multitudes." periodt.

🌸 SYNOPSIS 🌸

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

🎀 Flags:

  • --overwrite — lets your output files just bulldoze over existing files. no hesitation, no "are you sure", it simply eats them. be careful bestie, this is a real overwrite. 😭
  • --help — prints the usage summary, aka the "explain it to me like i'm five" button.
  • --verbose — verbose module output. it will not stop talking. honestly relatable.
  • --quiet — quiet module output. the opposite. it's giving mysterious. 🤫
  • --ui — force launches the GUI dialog. for when you want the pretty buttons instead of typing into the void.

🌈 Parameters:

  • input=name[,name,...] [required] — your bands, bestie. 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. yes that's the exact order, don't freestyle it, the math is not vibes-based. 🔥
  • output=basename [required] — basename for output raster map(s). also described as: name for output basename raster map(s). it's the name, it's a base, it's the base name, we move. ✨
  • sensor=string [required] — satellite sensor. your options are exactly: landsat4_tm, landsat5_tm, landsat7_etm, landsat8_oli, modis, sentinel2, worldview2. pick one, don't make one up, i'm begging. 🙈

💜 DESCRIPTION 💜

so i.tasscap calculates the Tasseled Cap (Kauth Thomas, TC) transformation for Landsat TM data (TM4, TM5, ETM7), MODIS and Sentinel-2 data. the tasseled cap transformation is effectively a compression method to reduce multiple spectral data into a few bands. iconic behavior honestly. the method was originally developed for understanding important phenomena of crop development in spectral space (Kauth and Thomas, 1976). crop development, in spectral space. main character energy from 1976.

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. so if you need to convert, that's your girl. 🫶

🌟 The tasseled cap components you get (yes, in order):

  • 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 one of those three, don't come looking for tasscap.4, she's not there. 💀

🦋 EXAMPLE 🦋

calculation of TC maps from a North Carolina Landsat 7 ETM scene. watch this:

# 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
  • ’Greenness’ Tasseled Cap component 2
  • ’Wetness’ Tasseled Cap component 3
  • ’Atmospheric haze’ Tasseled Cap component 4

ate. no crumbs. 🔥

📚 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.

that's the citation wall, bestie. we cite our sources in this house. 👑

👀 SEE ALSO 👀

i.albedo, i.atcorr, i.landsat.toar, i.vi

the whole friend group. go say hi. 🫶

🌸 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

legends, all of them, fr fr. 💖

📦 SOURCE CODE 📦

Available at: i.tasscap source code (history)

Accessed: Saturday Jan 17 05:41:52 2026

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

and that's the whole page, bestie! this manual came to you straight from the GRASS Development Team, © 2003-2025, GRASS GIS 8.4.2 Reference Manual, running on GRASS 8.4.2. bye bestie, go tassel that cap 💅✨🎀🦋

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