Enhancements

Built-in enhancement methods

stretch

The most basic operation is to stretch the image so that the data fits to the output format. There are many different ways to stretch the data, which are configured by giving them in kwargs dictionary, like in the example above. The default, if nothing else is defined, is to apply a linear stretch. For more details, see enhancing the images.

linear

As the name suggests, linear stretch converts the input values to output values in a linear fashion. By default, 5% of the data is cut on both ends of the scale, but these can be overridden with cutoffs=(0.005, 0.005) argument:

- name: stretch
  method: !!python/name:satpy.enhancements.stretch
  kwargs:
    stretch: linear
    cutoffs: [0.003, 0.005]

Note

This enhancement is currently not optimized for dask because it requires getting minimum/maximum information for the entire data array.

crude

The crude stretching is used to limit the input values to a certain range by clipping the data. This is followed by a linear stretch with no cutoffs specified (see above). Example:

- name: stretch
  method: !!python/name:satpy.enhancements.stretch
  kwargs:
    stretch: crude
    min_stretch: [0, 0, 0]
    max_stretch: [100, 100, 100]

It is worth noting that this stretch can also be used to _invert_ the data by giving larger values to the min_stretch than to max_stretch.

histogram

gamma

invert

crefl_scaling

Deprecated. Use ‘piecewise_linear_stretch’ instead.

piecewise_linear_stretch

Use numpy.interp() to linearly interpolate data to a new range. See satpy.enhancements.piecewise_linear_stretch() for more information and examples.

cira_stretch

Logarithmic stretch based on a cira recipe.

reinhard_to_srgb

Stretch method based on the Reinhard algorithm, using luminance.

The function includes conversion to sRGB colorspace.

Reinhard, Erik & Stark, Michael & Shirley, Peter & Ferwerda, James. (2002). Photographic Tone Reproduction For Digital Images. ACM Transactions on Graphics. :doi: 21. 10.1145/566654.566575

lookup

colorize

palettize

three_d_effect

The three_d_effect enhancement adds an 3D look to an image by convolving with a 3x3 kernel. User can adjust the strength of the effect by determining the weight (default: 1.0). Example:

- name: 3d_effect
  method: !!python/name:satpy.enhancements.three_d_effect
  kwargs:
    weight: 1.0