Lasinfo like task with lascatalog lidR

Question

I would like to have an idea about the classification of point clouds loaded in a LAScatalog with lidR. With a las file, I can do this way:

library(lidR)
LASfile <- system.file("extdata", "Megaplot.laz", package="lidR")
las <- readLAS(LASfile)
table(las$Classification)

How can I perform such queries with LAScatalog?

Answer 1

You have to read the files to get these information. The header of a las file does not store a summary of the classification. Consequently a LAScatalog cannot access such information because it only reads the headers. You can loop through your files:

lapply(files, function(file) {
  las <- readLAS(files, select = "c")
  table(las$Classification)
})