# eolearn.features.bands_extraction

A collection of bands extraction EOTasks

The task calculates the Euclidean Norm:

$$Norm = \sqrt{\sum_{i} B_i^2}$$

where $$B_i$$ are the individual bands within a user-specified feature array.

Parameters
• input_feature (an object supported by the FeatureParser) – A source feature from which to take the subset of bands.

• output_feature (an object supported by the FeatureParser) – An output feature to which to write the euclidean norm.

• bands (list) – A list of bands from which to extract the euclidean norm. If None, all bands are taken.

map_method(feature)[source]
Parameters

feature (numpy.array) – An eopatch on which to calculate the euclidean norm.

The task calculates a Normalized Difference Index (NDI) between two bands A and B as:

$$NDI = \dfrac{A-B+c}{A+B+c}$$,

where c is provided as the acorvi_constant argument. For the reasoning behind using the acorvi_constant in the equation, check the article Using NDVI with atmospherically corrected data.

Parameters
• input_feature (an object supported by the FeatureParser) – A source feature from which to take the bands.

• output_feature (an object supported by the FeatureParser) – An output feature to which to write the NDI.

• bands (list) – A list of bands from which to calculate the NDI.

• acorvi_constant (float) – A constant to be used in the NDI calculation. It is set to 0 by default.

• undefined_value – A value to override any calculation result that is not a finite value (e.g.: inf, nan).

map_method(feature)[source]
Parameters

feature (numpy.array) – An eopatch on which to calculate the NDI.