pyveg: A Python package for analysing the time evolution of patterned vegetation using Google Earth Engine

Periodic vegetation patterns (PVP) arise from the interplay between
forces that drive the growth and mortality of plants. Inter-plant
competition for resources, in particular water, can lead to the
formation of PVP. Arid and semi-arid ecosystems may be under threat
due to changing precipitation dynamics driven by macroscopic changes
in climate. These regions display some noteable examples of PVP,
for example the "tiger bush" patterns found in West Africa.

The morphology of the periodic pattern has been suggested to be
linked to the resilience of the ecosystem.
Using remote sensing techniques,  vegetation patterns in these regions
can be studied, and an analysis of the resilience of the ecosystem can
be performed.

The `pyveg` package implements functionality to download and process data
from Google Earth Engine (GEE), and to subsequently perform a
resilience analysis on the adquired data. PVP images are quantified using
network centrality metrics. The results of the analysis can be used
to search for typical early warning signals of an ecological collapse. Google Earth Engine Editor scripts are also provided to help
researchers discover locations of ecosystems which may be in
decline.

`pyveg` is being developed as part of a research project
looking for evidence of early warning signals of ecosystem
collapse using remote sensing data. `pyveg` allows such
research to be carried out at scale, and hence can be an
important tool in understanding changing arid and semi-arid
ecosystem dynamics.