Motivation for the package and its relation to adehabitatLT - mablab/rpostgisLT GitHub Wiki

Recent technological progress allowed ecologists to obtain a huge amount and diversity of animal movement data sets (usually from wildlife collars/sensors) of increasing spatial and temporal resolution and size, together with complex associated information related to the environmental context, such as habitat types based on remote sensing, population density, or weather. Such data often require the use of an integrated database system, and a solution of choice is the open-source database management system PostgreSQL, with its extension PostGIS, that adds support for spatial data. Storing spatial objects in a PostGIS-enabled database is particularly useful for movement data, which can be very large, regularly updated, and require cleaning and manipulation prior to being used in research.

On the other end of the process, the advancement of a movement ecology theoretical framework led to an unprecedented development of new analytical tools and methods, mostly available in the R statistical environment. The R package adehabitatLT is a collection of tools for the analysis of animal movements. In particular, it builds on a dedicated class for animal movement data (ltraj objects), which abstracts movement to a set of trajectories and its geometrical descriptors.

The package rpostgisLT focuses on streamlining the workflow for biologists storing/processing movement data in PostGIS and analyzing it in R, and aims at providing the tools to transparently benefit from the power of the most advanced database and statistical systems available for movement data. In particular, rpostgisLT provides full integration with data type ltraj from adehabitatLT with bi-directionnal conversion between PostGIS and R.

Before getting started with rpostgisLT, we recommend reading the vignette of adehabitatLT, which clearly defines a trajectory and its elements. Let us however repeat a few key concepts that are regularly used in this vignette. A trajectory is a continuous curve described by an animal, person or object when it moves. If a trajectory is sampled with e.g. a GPS tracker, each measurement represents a relocation, while the straight line segment that connects two successive relocations forms a step.