treepos_GWS: Find potential tree positions using a canopy height model

In uavRst: Unmanned Aerial Vehicle Remote Sensing Tools

Description

Find potential tree positions using a canopy height model by using an iterative watershed algorithm. Basically returns a vector data sets with the tree crown geometries and a bunch of corresponding indices.

Usage

treepos_GWS(
  chm = NULL,
  minTreeAlt = 10,
  minTreeAltParam = "chmQ20",
  minCrownArea = 3,
  maxCrownArea = 150,
  join = 1,
  thresh = 0.1,
  split = TRUE,
  cores = parallel::detectCores(),
  giLinks = NULL
)

Arguments

chm	raster* canopy height model
minTreeAlt	numeric. minimum height of trees to be integrated in the analysis
minTreeAltParam	character. code for the percentile that is used as tree height treshold. It is build using the key letters chmQ and adding the percentile i.e. "10". Default is chmQ20
minCrownArea	numeric. minimum area in square meter (if you use projected data) of the projected tree crowns
maxCrownArea	numeric. maximum area in square meter (if you use projected data) of the projected tree crowns
join	numeric. Join Segments based on Threshold Value, 0=no join, 1=treepos_GWS2saddle diff, 2=treepos_GWS2treepos diff. see also SAGA GIS Help
thresh	numeric. Specify a threshold value as minimum difference between neighboured segments in meter. see also SAGA GIS Help
split	split polygons default is TRUE
cores	number of cores to be used
giLinks	list. of GI tools cli paths

Value

raster* object

return raster* object

Author(s)

Chris Reudenbach

Examples

## Not run: 

# required packages
require(uavRst)
require(link2GI)

# create and check the links to the GI software
giLinks<-uavRst::linkGI()
if (giLinks$saga$exist & giLinks$otb$exist & giLinks$grass$exist) {

# project folder
projRootDir<-tempdir()

# create subfolders please mind that the pathes are exported as global variables
paths<-link2GI::initProj(projRootDir = projRootDir,
                         projFolders = c("data/","data/ref/","output/","run/","las/"),
                         global = TRUE,
                         path_prefix = "path_")

 data(chm_seg)

# calculate treepos using uavRst generic approach
 tPos <- uavRst::treepos_GWS(chm = chm_seg[[1]],
                         minTreeAlt = 2,
                         maxCrownArea = 150,
                         join = 1,
                         thresh = 0.35,
                         split=TRUE,
                         cores=1,
                         giLinks = giLinks )
}
##+
## End(Not run)

uavRst documentation built on Dec. 30, 2019, 5:06 p.m.