crown_filter: basic filtering of crown polygons using altitude, area and...

In uavRst: Unmanned Aerial Vehicle Remote Sensing Tools

Description

applies basic filtering of crown polygons using altitude, area and other optional thresholds. crown_filter basically returns SPDF with the crown polygons and all calculated parameters.

Usage

crown_filter(
  crownFn,
  minTreeAlt = 10,
  minCrownArea = 5,
  maxCrownArea = 100,
  minTreeAltParam = "chm_Q50",
  crownSTDW = NULL,
  opt = NULL,
  TAopt = NULL,
  proj4string = "+proj=utm +zone=32 +ellps=GRS80 +units=m +no_defs"
)

Arguments

crownFn	filname of OGR compliant vector file
minTreeAlt	minimum height in meter that will be regarded as tree
minCrownArea	minimum area of crowns that is accepted
maxCrownArea	maximum area of crowns that is accepted
minTreeAltParam	parameter that is used for filtering MinTreeAlt, default is Median "chmQ50"
crownSTDW	parameter that optionally filters for the STDV of the crown altitudes, default is NULL
opt	threshold value for optional filter, default is NULL
TAopt	optional parameter that might be used for filtering, default is NULL
proj4string	proj4 string

Author(s)

Chris Reudenbach

Examples

## Not run: 

 require(uavRst)
 require(link2GI)

# 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_")
# overide trailing backslash issue

# get the data
utils::download.file("https://github.com/gisma/gismaData/raw/master/uavRst/data/crowns.zip",
                       file.path(tempdir(),"crowns.zip"))
unzip(zipfile = file.path(tempdir(),"crowns.zip"), exdir =".")

 raster::plot(raster::shapefile(file.path(tempdir(),"polyStat.shp")))

# start postclassification of segements
tree_crowns <- crown_filter(crownFn =  file.path(tempdir(),"polyStat.shp"),
                             minTreeAlt = 3,
                             minCrownArea = 20,
                             maxCrownArea = 50,
                             minTreeAltParam = "chmQ20" )
# visualize it
raster::plot(tree_crowns[[2]])
##+
## End(Not run)

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