In this talk, we will present the SimpleSDMLayers package, which implements types and functions to interact with bioclimatic data and species distribution models in Julia. This package offers convenient integration between bioclimatic data and spatial coordinates, handles missing data, implements functions to download and manipulate WorldClim 2.0 data, and provides default plotting recipes allowing easier visualization of modelling results.
We will present the main features of the SimpleSDMLayers.jl package, and show how it allows convenient manipulation of species distribution modelling outputs. Species Distribution Models (SDMs) are widely used in Ecology and Biogeography, mainly to predict where environmental conditions should be suitable for a given species on continuous geographic scales. Hence, SDMs require strong integration between bioclimatic data and spatial coordinates. SimpleSDMLayers.jl, developed by Timothée Poisot and the EcoJulia organization, provides an efficient way to interact with these data in Julia, as well as a canvas on which SDM analyses can be built.
The package is built around the SimpleSDMLayer type, and stores bioclimatic data as layers. Each layer contains a grid field, which can store any type of data, as well as left, right, top, and bottom fields to store the bounding coordinates of a layer. This type allows extraction of data based on single coordinates or ranges. This type is intuitive and similar to the raster format used in Geographic Information Systems (GIS) for spatial data, while being easier to manipulate in the context of SDMs.
The package also implements default recipes for the Plots package, which allow efficient visualization and mapping of the bioclimatic variables and SDM outputs. The package handles missing data, and implements functions for operations such as resolution coarsening.
Another key feature of the package is its integration of the WorldClim 2.0 database, one of the most common source for climate data in SDM studies. WorldClim climate variable can be downloaded through the package and represented as SimpleSDMLayers. Theses layers can then be used in SDM models or represented using the plotting recipes of the package.
Our presentation will demonstrate the key features of the package through concrete examples of bioclimatic data visualization and species distribution modelling. It is aimed at ecologists and biogeographers in the Julia community, as well as all scientists working with spatial data.