Adding 'marks' to point file in spatstat?

Question

Using help on this site I have already got the following code from where I can perform certain analyses. However, I'd now like to perform analyses on a certain variable (column z) within the point shapefile. To do this I need to establish 'marks' on column z (the 7th column). This column provides either a '4' or a '10', defining two types of point.

Can anyone assist?

##Run libraries: 
library(“spatstat”)
library(“maptools”)
library(“sp”)
library(“rgdal”)

##set the working directory
setwd(“Z:/CP/spatstat/data/”)

##read in the shapefiles
Points <- readOGR(getwd(), "MyPointShapefile")
StudyArea <- readOGR(getwd(), "MyPolygonShapefile")

##create the window from polygon shp
w <- as.owin(StudyArea)

##coerce the points to window
pts.ppp <- as.ppp(coordinates(Points), w)
plot(pts.ppp)

Answer 1

If the marks are created based off another attribute, then you could probably just use an if-else statement. You can simply create a new column by creating a variable ie.

Points$NewMarks <- ifelse(X, Y, Z)

Where:

X = Your argument (if statement), Y = Your then statement (for you: 4), and Z = Else statement (for you: 10)