Introduction

In this workshop we will use the spatstat package in R (actually spatstat is an umbrella for a collection of packages):

library(spatstat)
## Loading required package: spatstat.data
## Loading required package: spatstat.geom
## spatstat.geom 2.4-0
## Loading required package: spatstat.random
## spatstat.random 2.2-0
## Loading required package: spatstat.core
## Loading required package: nlme
## Loading required package: rpart
## spatstat.core 2.4-4
## Loading required package: spatstat.linnet
## spatstat.linnet 2.3-2
## 
## spatstat 2.3-4       (nickname: 'Watch this space') 
## For an introduction to spatstat, type 'beginner'

Spatial data= data attributed to spatial locations

Three main types of spatial data:

This workshop is about the analysis of spatial point patterns, and this is also the main focus of the spatstat package.

Spatial point pattern terminology

Points

The “points” in a point pattern are the spatial locations where the events or objects were observed. They are specified by spatial coordinates. NOTE: In all that follows and for all functions in spatstat the coordinates are assumed to be projected coordinates in Euclidean space. Do not analyse geographic coordinates (latitude and longitude) directly in spatstat – project them first! (Using e.g. the sf package.)

Window

The window \(W\) is the spatial region where points were (or could have been) observed.

Covariates

Covariates are explanatory variables (which might “explain” any spatial variation in the abundance of points, for example).

Many covariates take the form of a function \(Z(u), \quad u \in W\) defined at every spatial location \(u\).

Alternatively, other kinds of spatial data can be treated as explanatory data. Usually we need to translate them into spatial functions for use in analysis.

Marks

Marks are attributes of the individual events or things.

In a spatial point pattern of trees, the trees might be classified into different species, and each tree carries a mark (“label”) indicating which species it belongs to.