dea_tools.bandindices

Calculating band indices from remote sensing data (NDVI, NDWI etc).

License: The code in this notebook is licensed under the Apache License, Version 2.0 (https://www.apache.org/licenses/LICENSE-2.0). Digital Earth Australia data is licensed under the Creative Commons by Attribution 4.0 license (https://creativecommons.org/licenses/by/4.0/).

Contact: If you need assistance, please post a question on the Open Data Cube Discord chat (https://discord.com/invite/4hhBQVas5U) or on the GIS Stack Exchange (https://gis.stackexchange.com/questions/ask?tags=open-data-cube) using the open-data-cube tag (you can view previously asked questions here: https://gis.stackexchange.com/questions/tagged/open-data-cube).

If you would like to report an issue with this script, you can file one on GitHub (GeoscienceAustralia/dea-notebooks#new).

Last modified: June 2023

Functions

calculate_indices(ds[, index, collection, ...])

Takes an xarray dataset containing spectral bands, calculates one of a set of remote sensing indices, and adds the resulting array as a new variable in the original dataset.
dea_tools.bandindices.calculate_indices(ds, index=None, collection=None, custom_varname=None, normalise=True, drop=False, inplace=False)[source]

Takes an xarray dataset containing spectral bands, calculates one of a set of remote sensing indices, and adds the resulting array as a new variable in the original dataset.

Note: by default, this function will create a new copy of the data in memory. This can be a memory-expensive operation, so to avoid this, set inplace=True.

Last modified: June 2023

Parameters:

  • ds (xarray Dataset) – A two-dimensional or multi-dimensional array with containing the spectral bands required to calculate the index. These bands are used as inputs to calculate the selected water index.

  • index (str or list of strs) –

    A string giving the name of the index to calculate or a list of strings giving the names of the indices to calculate:

    • 'AWEI_ns' (Automated Water Extraction Index,

      no shadows, Feyisa 2014)

    • 'AWEI_sh' (Automated Water Extraction Index,

      shadows, Feyisa 2014)

    • 'BAEI' (Built-Up Area Extraction Index, Bouzekri et al. 2015)

    • 'BAI' (Burn Area Index, Martin 1998)

    • 'BSI' (Bare Soil Index, Rikimaru et al. 2002)

    • 'BUI' (Built-Up Index, He et al. 2010)

    • 'CMR' (Clay Minerals Ratio, Drury 1987)

    • 'EVI' (Enhanced Vegetation Index, Huete 2002)

    • 'FMR' (Ferrous Minerals Ratio, Segal 1982)

    • 'IOR' (Iron Oxide Ratio, Segal 1982)

    • 'LAI' (Leaf Area Index, Boegh 2002)

    • 'MNDWI' (Modified Normalised Difference Water Index, Xu 1996)

    • 'MSAVI' (Modified Soil Adjusted Vegetation Index,

      Qi et al. 1994)

    • 'NBI' (New Built-Up Index, Jieli et al. 2010)

    • 'NBR' (Normalised Burn Ratio, Lopez Garcia 1991)

    • 'NDBI' (Normalised Difference Built-Up Index, Zha 2003)

    • 'NDCI' (Normalised Difference Chlorophyll Index,

      Mishra & Mishra, 2012)

    • 'NDMI' (Normalised Difference Moisture Index, Gao 1996)

    • 'NDSI' (Normalised Difference Snow Index, Hall 1995)

    • 'NDTI' (Normalise Difference Tillage Index,

      Van Deventeret et al. 1997)

    • 'NDTI2' (Normalised Difference Turbidity Index, Lacaux et al., 2007)

    • 'NDVI' (Normalised Difference Vegetation Index, Rouse 1973)

    • 'NDWI' (Normalised Difference Water Index, McFeeters 1996)

    • 'SAVI' (Soil Adjusted Vegetation Index, Huete 1988)

    • 'TCB' (Tasseled Cap Brightness, Crist 1985)

    • 'TCG' (Tasseled Cap Greeness, Crist 1985)

    • 'TCW' (Tasseled Cap Wetness, Crist 1985)

    • 'TCB_GSO' (Tasseled Cap Brightness, Nedkov 2017)

    • 'TCG_GSO' (Tasseled Cap Greeness, Nedkov 2017)

    • 'TCW_GSO' (Tasseled Cap Wetness, Nedkov 2017)

    • 'WI' (Water Index, Fisher 2016)

    • 'kNDVI' (Non-linear Normalised Difference Vegation Index,

      Camps-Valls et al. 2021)

  • collection (str) –

    An string that tells the function what data collection is being used to calculate the index. This is necessary because different collections use different names for bands covering a similar spectra.

    Valid options are:

    • 'ga_ls_3' (for GA Landsat Collection 3)

    • 'ga_s2_3' (for GA Sentinel 2 Collection 3)

    • 'ga_gm_3' (for GA Geomedian Collection 3)

  • custom_varname (str, optional) – By default, the original dataset will be returned with a new index variable named after index (e.g. ‘NDVI’). To specify a custom name instead, you can supply e.g. custom_varname=’custom_name’. Defaults to None, which uses index to name the variable.

  • normalise (bool, optional) – Some coefficient-based indices (e.g. 'WI', 'BAEI', 'AWEI_ns', 'AWEI_sh', 'TCW', 'TCG', 'TCB', 'TCW_GSO', 'TCG_GSO', 'TCB_GSO', 'EVI', 'LAI', 'SAVI', 'MSAVI') produce different results if surface reflectance values are not scaled between 0.0 and 1.0 prior to calculating the index. Setting normalise=True first scales values to a 0.0-1.0 range by dividing by 10000.0. Defaults to True.

  • drop (bool, optional) – Provides the option to drop the original input data, thus saving space. if drop = True, returns only the index and its values.

  • inplace (bool, optional) – If inplace=True, calculate_indices will modify the original array in-place, adding bands to the input dataset. The default is inplace=False, which will instead make a new copy of the original data (and use twice the memory).

Returns:

ds – The original xarray Dataset inputted into the function, with a new varible containing the remote sensing index as a DataArray. If drop = True, the new variable/s as DataArrays in the original Dataset.

Return type:

xarray Dataset