I have the data here

However, the circle and the triangle are not clear without colouring I think. How can I colour the triangle so it will be more obvious to see? Or change the triangle to a coloured circle? I have tried using the code mentioned above but nothing has change.

CodePudding user response：

Use argument cols to specify colours for the different types of points, and chars to specify the plotting symbols for the different types of points. You could also use cex to control the size of the plot symbols to make them more distinct.

For further information see the help file for plot.ppp.