Stop the pipeline conditionally. The stages after a `stop_if` stage are skipped if the condition is met. This allows to process a subset of the dataset of to skip some stages conditionally. This DOES NOT stop the computation. In only breaks the pipeline for the current file/chunk currently processed. (see exemple)
Examples
# Collection of 4 files
f <- system.file("extdata", "bcts/", package="lasR")
# This bounding box encompasses only one of the four files
stopif = stop_if_outside(884800, 620000, 885400, 629200)
read = reader()
hll = hulls()
tri = triangulate(filter = keep_ground())
dtm = rasterize(1, tri)
# reads the 4 files but 'tri' and 'dtm' are computed only for one file because stopif
# allows to escape the pipeline outside the bounding box
pipeline = read + hll + stopif + tri + dtm
ans1 <- exec(pipeline, on = f)
plot(ans1$hulls$geom, axes = TRUE)
terra::plot(ans1$rasterize, add = TRUE)
# stopif can be applied before read. Only one file will actually be read and processed
pipeline = stopif + read + hll + tri + dtm
ans2 <- exec(pipeline, on = f)
plot(ans2$hulls$geom, axes = TRUE)
terra::plot(ans1$rasterize, add = TRUE, legend = FALSE)
