rotatepolygon

Rotate the input polygon with a given angle and around a fix point. Function adapted from Jeffrey Evans' 'rotate.polygon' function: https://github.com/jeffreyevans/spatialEco/blob/master/R/rotate.polygon.R

Usage

rotatepolygon(p, angle, fixed)

Arguments

p

Polygon (POLYGON or sfc_POLYGON)

angle

Angle in degrees in the clockwise direction (numeric)

fixed

Fix point around which the polygon will be rotated (POINT)

Value

The polygon (sfc_POLYGON) rotated.

Examples

data(Paracou6_2016)
data(DTMParacou)
data(SpeciesCriteria)
data(MainTrails)

inventory <- addtreedim(cleaninventory(Paracou6_2016, PlotMask),
volumeparameters = ForestZoneVolumeParametersTable)

inventory <- suppressMessages(treeselection(inventory,
topography = DTMParacou,
speciescriteria = SpeciesCriteria,
scenario = "manual", objective = 10, fuel = "2", diversification = TRUE,
winching = "0", specieslax = FALSE, objectivelax = TRUE,
plotslope = HarvestableAreaOutputsCable$PlotSlope,
maintrails = MainTrails,
harvestablearea = HarvestableAreaOutputsCable$HarvestableArea,
harvestablepolygons = HarvestableAreaOutputsCable$HarvestablePolygons,
advancedloggingparameters = loggingparameters())$inventory)

inventory <- inventory %>%
     dplyr::filter(Selected == "1") %>%
     dplyr::select(idTree,DBH,TrunkHeight,TreeHeight,CrownHeight,
     CrownDiameter,Selected, Xutm, Yutm)
dat <- inventory[1,]

library(sf)
library(nngeo)
library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:raster’:
#> 
#>     intersect, select, union
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union
Foot <- st_point(c(dat$Xutm,dat$Yutm)) # tree foot point
Crown <- dat %>%
dplyr::mutate(xCrown = Xutm,
       yCrown = Yutm + TrunkHeight + CrownHeight/2,
       exCrown = CrownDiameter/2,
       eyCrown = CrownHeight/2) %>%
sf::st_as_sf(coords = c("xCrown", "yCrown")) # ellipse centroid coordinates
Crown <- st_ellipse(Crown, Crown$exCrown, Crown$eyCrown) # create the ellipse
Trunk <- with(dat, # and the trunk
              st_polygon(list(matrix(c(Xutm-(DBH/100)/2, Yutm,
                                      Xutm-(DBH/100)/2, Yutm + TrunkHeight,
                                      Xutm+(DBH/100)/2, Yutm + TrunkHeight,
                                      Xutm+(DBH/100)/2, Yutm,
                                      Xutm-(DBH/100)/2, Yutm) # the return
                                    ,ncol=2, byrow=TRUE))))
 RandomAngle <- as.numeric(sample(c(0:359), size = 1))

 TreeP <- st_difference(st_union(
 rotatepolygon(Trunk, angle = RandomAngle, fixed = Foot), # turned trunk
 rotatepolygon(Crown, angle = RandomAngle, fixed = Foot) # turned crown
 ))

library(ggplot2)
 ggplot() +
  geom_sf(data = st_union(Trunk, Crown), colour = "red") +
  geom_sf(data = TreeP, colour = "green")