This is the first stage that must be called in each pipeline. The stage does nothing and returns
nothing if it is not associated to another processing stage.
It only initializes the pipeline. reader() is the main function that dispatches into to other
functions. reader_coverage() processes the entire point cloud. reader_circles() and
reader_rectangles() read and process only some selected regions of interest. If the chosen
reader has no options i.e. using reader() it can be omitted.
Usage
reader(filter = "", select = "*", copc_depth = NULL, ...)
reader_coverage(filter = "", select = "*", copc_depth = NULL, ...)
reader_circles(xc, yc, r, filter = "", select = "*", copc_depth = NULL, ...)
reader_rectangles(
xmin,
ymin,
xmax,
ymax,
filter = "",
select = "*",
copc_depth = NULL,
...
)Arguments
- filter
the 'filter' argument allows filtering of the point-cloud to work with points of interest. For a given stage when a filter is applied, only the points that meet the criteria are processed. The most common strings are
Classification == 2","Z > 2","Intensity < 100". For more details see filters.- select
character. Unused. Reserved for future versions.
- copc_depth
integer. If the files are COPC file is is possible to read the point hierarchy up to a given level.
- ...
passed to other readers
- xc, yc, r
numeric. Circle centres and radius or radii.
- xmin, ymin, xmax, ymax
numeric. Coordinates of the rectangles
Examples
f <- system.file("extdata", "Topography.las", package = "lasR")
pipeline <- reader() + rasterize(10, "zmax")
ans <- exec(pipeline, on = f)
# terra::plot(ans)
pipeline <- reader(filter = keep_z_above(1.3)) + rasterize(10, "zmean")
ans <- exec(pipeline, on = f)
# terra::plot(ans)
# read_las() with no option can be omitted
ans <- exec(rasterize(10, "zmax"), on = f)
# terra::plot(ans)
# Perform a query and apply the pipeline on a subset
pipeline = reader_circles(273500, 5274500, 20) + rasterize(2, "zmax")
ans <- exec(pipeline, on = f)
# terra::plot(ans)
# Perform a query and apply the pipeline on a subset with 1 output files per query
ofile = paste0(tempdir(), "/*_chm.tif")
pipeline = reader_circles(273500, 5274500, 20) + rasterize(2, "zmax", ofile = ofile)
ans <- exec(pipeline, on = f)
# terra::plot(ans)