Composites

Documentation coming soon…

Modifiers

Making custom composites

Note

These features will be added to the Scene object in the future.

Building custom composites makes use of the GenericCompositor class. For example, building an overview composite can be done manually with:

>>> from satpy.composites import GenericCompositor
>>> compositor = GenericCompositor("myoverview", "bla", "")
>>> composite = compositor([local_scene[0.6],
...                         local_scene[0.8],
...                         local_scene[10.8]])
>>> from satpy.writers import to_image
>>> img = to_image(composite)
>>> img.invert([False, False, True])
>>> img.stretch("linear")
>>> img.gamma(1.7)
>>> img.show()

One important thing to notice is that there is an internal difference between a composite and an image. A composite is defined as a special dataset which may have several bands (like R, G, B bands). However, the data isn’t stretched, or clipped or gamma filtered until an image is generated.

To save the custom composite, the following procedure can be used:

  1. Create a custom directory for your custom configs.
  2. Set it in the environment variable called PPP_CONFIG_DIR.
  3. Write config files with your changes only (look at eg satpy/etc/composites/seviri.yaml for inspiration), pointing to the custom module containing your composites. Don’t forget to add changes to the enhancement/generic.cfg file too.
  4. Put your composites module on the python path.

With that, you should be able to load your new composite directly.