From b0a2579c68604037988b8256e1577973610a3596 Mon Sep 17 00:00:00 2001 From: David Hoese Date: Fri, 17 Nov 2023 09:56:46 -0600 Subject: [PATCH] Add more information to slice caching config documentation --- docs/source/howtos/configuration.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/docs/source/howtos/configuration.rst b/docs/source/howtos/configuration.rst index fe1606350..6a79acf10 100644 --- a/docs/source/howtos/configuration.rst +++ b/docs/source/howtos/configuration.rst @@ -117,6 +117,17 @@ are cached, this option saves a pair of ``slice`` objects that consist of only 3 integers each. This makes the amount of space used in the cache very small for many cached results. +The slicing operations in Pyresample typically involve finding the intersection +between two geometries. This requires generating bounding polygons for the +geometries and doing polygon intersection calculations that can handle +projection anti-meridians. At the time of writing these calculations can take +as long as 15 seconds depending on number of vertices used in the bounding +polygons. One use case for these slices is reducing input data to only the +overlap of the target area. This can be done before or during resampling as +part of the algorithm or as part of a third-party resampling interface +(ex. Satpy). In the future as optimizations are made to the polygon +intersection logic this caching option should hopefully not be needed. + When setting this as an environment variable, this should be set with the string equivalent of the Python boolean values ``="True"`` or ``="False"``.