GapSPDF: Forest Canopy Gaps as Spatial Polygons

In ForestGapR: Tropical Forest Canopy Gaps Analysis

Description

This function converts forest canopy gaps as raster::RasterLayer to sp::SpatialPointsDataFrame objects

Usage

GapSPDF(gap_layer)

Arguments

gap_layer

ALS-derived gap layer (output of getForestGaps() function). An object of the class RasterLayer.

Value

A sp::SpatialPointsDataFrame object of the forest canopy gaps. The output file can be exported as a ESRI shapefile using rgdal::writeOGR() function in the rgdal package.

Author(s)

Carlos Alberto Silva.

Examples

# Loading raster and viridis libraries
library(raster)
library(viridis)

# ALS-derived CHM over Adolpho Ducke Forest Reserve - Brazilian tropical forest
data(ALS_CHM_DUC)

# set height thresholds (e.g. 10 meters)
threshold <- 10
size <- c(1, 10^4) # m2

# Detecting forest gaps
gaps_duc <- getForestGaps(chm_layer = ALS_CHM_DUC, threshold = threshold, size = size)

# Converting raster layer to SpatialPolygonsDataFrame
gaps_spdf <- GapSPDF(gap_layer = gaps_duc)

# Plotting ALS-derived CHM and forest gaps
plot(ALS_CHM_DUC, col = viridis(10), xlim = c(173025, 173125), ylim = c(9673100, 96731200))
plot(gaps_spdf, add = TRUE, border = "red", lwd = 2)

# Populating the attribute table of Gaps_spdf with gaps statistics
gaps_stats <- GapStats(gap_layer = gaps_duc, chm_layer = ALS_CHM_DUC)
gaps_spdf <- merge(gaps_spdf, gaps_stats, by = "gap_id")
head(gaps_spdf@data)

ForestGapR documentation built on Oct. 3, 2021, 3 a.m.