Title:	Modeling Species Distributions in Three Dimensions
Version:	0.2.3
Maintainer:	Hannah L. Owens <hannah.owens@gmail.com>
Description:	Facilitates modeling species' ecological niches and geographic distributions based on occurrences and environments that have a vertical as well as horizontal component, and projecting models into three-dimensional geographic space. Working in three dimensions is useful in an aquatic context when the organisms one wishes to model can be found across a wide range of depths in the water column. The package also contains functions to automatically generate marine training model training regions using machine learning, and interpolate and smooth patchily sampled environmental rasters using thin plate splines. Davis Rabosky AR, Cox CL, Rabosky DL, Title PO, Holmes IA, Feldman A, McGuire JA (2016) <doi:10.1038/ncomms11484>. Nychka D, Furrer R, Paige J, Sain S (2021) <doi:10.5065/D6W957CT>. Pateiro-Lopez B, Rodriguez-Casal A (2022) https://CRAN.R-project.org/package=alphahull.
License:	GPL-3
URL:	https://hannahlowens.github.io/voluModel/
BugReports:	https://github.com/hannahlowens/voluModel/issues
Encoding:	UTF-8
Depends:	R (≥ 4.0.0)
Imports:	dplyr, fields, ggplot2, ggtext, grDevices, methods, metR, modEvA, rangeBuilder (≥ 2.0), rnaturalearth, terra, viridisLite, sf
Suggests:	testthat (≥ 3.0.0), nlme, knitr, covr, gridExtra, lattice, rmarkdown, rnaturalearthdata, tibble
VignetteBuilder:	knitr
RoxygenNote:	7.3.2
Config/testthat/edition:	3
NeedsCompilation:	no
Packaged:	2025-07-18 15:55:56 UTC; HannahOwens
Author:	Hannah L. Owens [aut, cre], Emmaline Sheahan [aut], Carsten Rahbek [aut]
Repository:	CRAN
Date/Publication:	2025-07-18 23:00:02 UTC

Calculate MESS

Description

Calculates multivariate environmental similarity surface based on model calibration and projection data

Usage

MESS3D(calibration, projection)

Arguments

Details

MESS3D is a wrapper around MESS from the modEvA package. It calculates MESS for each depth layer. Negative values indicate areas of extrapolation which should be interpreted with caution (see Elith et al, 2010 in MEE).

Value

A SpatRaster vector with MESS scores for each voxel; layer names correspond to layer names of first SpatRaster vector in projection list.

Note

The calibration dataset should include both presences and background/pseudoabsence points used to calibrate an ecological niche model.

References

Elith J, Kearney M, and Phillips S. 2010. The art of modelling range-shifting species. Methods in Ecology and Evolution, 1, 330-342.

See Also

MESS

Examples

library(terra)
library(dplyr)

# Create sample rasterBricks
r1 <- rast(ncol=10, nrow=10)
values(r1) <- 1:100
r2 <- rast(ncol=10, nrow=10)
values(r2) <- c(rep(20, times = 50), rep(60, times = 50))
r3 <- rast(ncol=10, nrow=10)
values(r3) <- 8
envBrick1 <- c(r1, r2, r3)
names(envBrick1) <- c(0, 10, 30)

r1 <- rast(ncol=10, nrow=10)
values(r1) <- 100:1
r2 <- rast(ncol=10, nrow=10)
values(r2) <- c(rep(10, times = 50), rep(20, times = 50))
r3 <- rast(ncol=10, nrow=10)
values(r3) <- c(rep(c(10,20,30,25), times = 25))
envBrick2 <- c(r1, r2, r3)
names(envBrick2) <- c(0, 10, 30)

rastList <- list("temperature" = envBrick1, "salinity" = envBrick2)

# Create test reference set
set.seed(0)
longitude <- sample(ext(envBrick1)[1]:ext(envBrick1)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(envBrick1)[3]:ext(envBrick1)[4],
                   size = 10, replace = FALSE)
set.seed(0)
depth <- sample(0:35, size = 10, replace = TRUE)
occurrences <- as.data.frame(cbind(longitude,latitude,depth))

# Calibration
calibration <- lapply(rastList, FUN = function(x) xyzSample(occurrences, x)) %>% bind_rows

# Run the function
messStack <- MESS3D(calibration = calibration, projection = rastList)
plot(messStack)

Are Colors

Description

Checks to see if a given vector can be interpreted by R as a color or colors

Usage

areColors(col)

Arguments

Value

A logical vector stating whether inputs can be interpreted as colors.

Examples

areColors(col = c("red", "prairie_chicken", 2))

Blend Colors

Description

Generates a blended color from two transparent colors

Usage

blendColor(col1 = "#1b9e777F", col2 = "#7570b37F")

Arguments

Value

A character string with hex color, including adjustment for transparency.

Examples

blendColor(col1 = "#1B9E777F", col2 = "#7570B37F")

Bottom raster generation

Description

Samples deepest depth values from a SpatVector data frame and generates a SpatRaster.

Usage

bottomRaster(rawPointData)

Arguments

Details

rawPointData is a SpatVector object that contains measurements of a single environmental variable (e.g. salinity, temperature, etc.) with x, y, and z coordinates. The measurements in the data.frame should be organized so that each column is a depth slice, increasing in depth from left to right. The function was designed around the oceanographic data shapefiles supplied by the World Ocean Atlas (https://www.ncei.noaa.gov/access/world-ocean-atlas-2018/). The function selects the "deepest" (rightmost) measurement at each x, y coordinate pair that contains data. These measurements are then rasterized at the resolution and extent of the x,y coordinates, under the assumption that x and y intervals are equal and represent the center of a cell.

Value

A SpatRaster designed to approximate sea bottom measurements for modeling species' distributions and/or niches.

Examples

library(terra)

# Create point grid
coords <- data.frame(x = rep(seq(1:5), times = 5),
                    y = unlist(lapply(1:5, FUN = function(x) {
                      rep(x, times = 5)})))

# Create data and add NAs to simulate uneven bottom depths
dd <- data.frame(SURFACE = 1:25,
                d5M = 6:30,
                d10M = 11:35,
                d25M = 16:40)
dd$d25M[c(1:5, 18:25)] <- NA
dd$d10M[c(3:5, 21:23)] <- NA
dd$d5M[c(4, 22)] <- NA

dd[,c("x","y")] <- coords

# Create SpatialPointsDataFrame
sp <- vect(dd, geom = c("x", "y"))

# Here's the function
result <- bottomRaster(rawPointData = sp)
plot(result)

Center Point Raster Template

Description

Creates a SpatRaster template from a SpatVector point object in which the raster cells are centered on the vector points.

Usage

centerPointRasterTemplate(rawPointData)

Arguments

Details

rawPointData is a SpatVector object that contains x and y coordinates.

Value

An empty SpatRaster designed to serve as a template for rasterizing SpatVector objects.

See Also

rasterize

Examples

library(terra)

# Create point grid
coords <- data.frame(x = rep(seq(1:5), times = 5),
                    y = unlist(lapply(1:5, FUN = function(x) {
                      rep(x, times = 5)})))

# Create data and add NAs to simulate uneven bottom depths
dd <- data.frame(SURFACE = 1:25,
                d5M = 6:30,
                d10M = 11:35,
                d25M = 16:40)
dd$d25M[c(1:5, 18:25)] <- NA
dd$d10M[c(3:5, 21:23)] <- NA
dd$d5M[c(4, 22)] <- NA

dd[,c("x","y")] <- coords

# Create SpatialPointsDataFrame
sp <- vect(dd, geom = c("x", "y"))

# Here's the function
template <- centerPointRasterTemplate(rawPointData = sp)
class(template)

Column Parsing

Description

Parses column names from input occurrence data.frame for more seamless function

Usage

columnParse(occs, wDepth = FALSE)

Arguments

Details

This is an internal function to return the putative indices for latitude and longitude or x and y coordinates of occurrences to allow for code that is more robust to very common user error

Value

A list of length 2 with indices of the x and y columns, respectively, followed by a message with a plain text report of which columns were interpreted as x and y.

Examples

library(terra)

# Create sample raster
r <- rast(ncol=10, nrow=10)
values(r) <- 1:100

# Create test occurrences
set.seed(0)
longitude <- sample(ext(r)[1]:ext(r)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(r)[3]:ext(r)[4],
                   size = 10, replace = FALSE)
set.seed(0)
depth <- sample(0:35, size = 10, replace = TRUE)
occurrences <- as.data.frame(cbind(longitude,latitude,depth))

# Here's the function
result <- columnParse(occs = occurrences[,1:2],
                      wDepth = FALSE)
result <- columnParse(occs = occurrences,
                      wDepth = TRUE)

Diversity stack

Description

Takes list of rasters of species distributions (interpreted as 1 = presence, 0 = absence), which do not have to have the same extents, and stack them to create an estimate of species richness that matches the extent and resolution of a template.

Usage

diversityStack(rasterList, template)

Arguments

Value

A SpatRaster

Examples

library(terra)
rast1 <- rast(ncol=10, nrow=10)
values(rast1) <- rep(0:1, 50)

rast2 <- rast(ncol=10, nrow=10)
values(rast2) <- c(rep(0, 50), rep(1,50))

rastList <- list(rast1, rast2)
result <- diversityStack(rasterList = rastList,
                         template = rast2)
result
plot(result)

Occurrence downsampling

Description

Reduces number of occurrences to resolution of input raster

Usage

downsample(occs, rasterTemplate, verbose = TRUE)

Arguments

Value

A data.frame with two columns named "longitude" and "latitude" or with names that were used when coercing input data into this format.

Examples

library(terra)
# Create sample raster
r <- rast(ncol=10, nrow=10)
values(r) <- 1:100

# Create test occurrences
set.seed(0)
longitude <- sample(ext(r)[1]:ext(r)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(r)[3]:ext(r)[4],
                   size = 10, replace = FALSE)
occurrences <- as.data.frame(cbind(longitude,latitude))

# Here's the function
result <- downsample(occs = occurrences, rasterTemplate = r)

Interpolate patchily sampled rasters

Description

Uses thin plate spline regression from fields package to interpolate missing two-dimensional raster values.

Usage

interpolateRaster(inputRaster, fast = FALSE, ...)

Arguments

Details

Missing data values from original raster are replaced with interpolated values. User has the option of choosing fastTps to speed calculation, but be advised that this is only an approximation of a true thin plate spline.

Value

An object of class raster

See Also

Tps, fastTps

Examples

library(terra)
library(fields)
# Create sample raster
r <- rast(ncol=50, nrow=50)
values(r) <- 1:2500

# Introduce a "hole"
values(r)[c(117:127, 167:177, 500:550)] <- NA
plot(r)

# Patch hole with interpolateRaster
interpolatedRaster <- interpolateRaster(r)
plot(interpolatedRaster)
fastInterp <- interpolateRaster(r, fast = TRUE, aRange = 3.0)
plot(fastInterp)

2D background sampling

Description

Samples in 2D at resolution of raster

Usage

mSampling2D(occs, rasterTemplate, mShp, verbose = TRUE)

Arguments

Details

This function is designed to sample background points for distributional modeling in two dimensions. The returned data.frame contains all points from across the designated background. It is up to the user to determine how to appropriately sample from those background points.

Value

A data.frame with 2D coordinates of points for background sampling.

Examples

library(terra)

# Create sample raster
r <- rast(ncol=10, nrow=10)
values(r) <- 1:100

# Create test occurrences
set.seed(0)
longitude <- sample(ext(r)[1]:ext(r)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(r)[3]:ext(r)[4],
                   size = 10, replace = FALSE)
occurrences <- data.frame(longitude,latitude)

# Generate background sampling buffer
buffPts <- vect(occurrences,
                c("longitude", "latitude"))
crs(buffPts) <- crs(r)
mShp <- aggregate(buffer(buffPts, width = 1000000))

# Here's the function
result <- mSampling2D(occs = occurrences, rasterTemplate = r, mShp = mShp)

3D background sampling

Description

Samples XYZ coordinates from a shapefile from maximum to minimum occurrence depth at XYZ resolution of envBrick.

Usage

mSampling3D(occs, envBrick, mShp, depthLimit = "all", verbose = TRUE)

Arguments

Details

This function is designed to sample background points for distributional modeling in three dimensions. If a voxel (3D pixel) in the SpatRaster vector intersects with an occurrence from occs, it is removed. Note that this function returns points representing every voxel in the background area within the specified depth range. It is up to the user to downsample from these data as necessary, depending on the model type being used.

depthLimit argument options:

• occs Samples background from the full depth extent of occs.

• all Samples background from the full depth extent of envBrick.

• A vector of length 2 with maximum and minimum depth values from which to sample.

Value

A data.frame with 3D coordinates of points for background sampling.

Examples

library(terra)

# Create test raster
r1 <- rast(ncol=10, nrow=10)
values(r1) <- 1:100
r2 <- rast(ncol=10, nrow=10)
values(r2) <- c(rep(20, times = 50), rep(60, times = 50))
r3 <- rast(ncol=10, nrow=10)
values(r3) <- 8
envBrick <- c(r1, r2, r3)
names(envBrick) <- c(0, 10, 30)

# Create test occurrences
set.seed(0)
longitude <- sample(ext(envBrick)[1]:ext(envBrick)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(envBrick)[3]:ext(envBrick)[4],
                   size = 10, replace = FALSE)
set.seed(0)
depth <- sample(0:35, size = 10, replace = TRUE)
occurrences <- data.frame(longitude,latitude,depth)

# Generate background sampling buffer
buffPts <- vect(occurrences,
                c("longitude", "latitude"))
crs(buffPts) <- crs(envBrick)
mShp <- aggregate(buffer(buffPts, width = 1000000))

# Here's the function
occSample3d <- mSampling3D(occs = occurrences,
                           envBrick = envBrick,
                           mShp = mShp,
                           depthLimit = "occs")

Marine background shapefile generation

Description

Automatically generates background shapefiles for sampling pseudoabsences and/or background points for niche modeling or species distribution modeling. Delineating background sampling regions can be one of the trickiest parts of generating a good model. Automatically generated background shapefiles should be inspected carefully prior to model use.

Useful references, among others:

• Barve N, Barve V, Jiménez-Valverde A, Lira-Noriega A, Maher SP, Peterson AT, Soberón J, Villalobos F. 2011. The crucial role of the accessible area in ecological niche modeling and species distribution modeling. Ecological modelling 222:1810-9.

• Merow, C, Smith MJ, Silander JA. 2013. A practical guide to MaxEnt for modeling species’ distributions: what it does, and why inputs and settings matter." Ecography 36: 1058-69.

• Murphy SJ. 2021. Sampling units derived from geopolitical boundaries bias biodiversity analyses. Global Ecology and Biogeography 30: 1876-88.

Usage

marineBackground(occs, clipToOcean = TRUE, verbose = TRUE, ...)

Arguments

Details

The meat of this function is a special-case wrapper around getDynamicAlphaHull() from the rangeBuilder package. The function documented here is especially useful in cases where one wants to automatically generate training regions that overlap the international date line. Regions that exceed the line are cut and pasted into the appropriate hemisphere instead of being deleted.

If the argument buff is not supplied, a buffer is calculated by taking the mean between the 10th and 90th percentile of horizontal distances between occurrence points.

If getDynamicAlphaHull() cannot satisfy the provided conditions, the occurrences are buffered and then a minimum convex hull is drawn around the buffer polygons.

Value

A SpatVector

See Also

getDynamicAlphaHull

Examples

library(terra)
# Create sample raster
r <- rast(ncol=10, nrow=10)
values(r) <- 1:100

# Create test occurrences
set.seed(0)
longitude <- sample(-50:50,
                    size = 20, replace = FALSE)
set.seed(0)
latitude <- sample(-30:30,
                   size = 20, replace = FALSE)
occurrences <- as.data.frame(cbind(longitude,latitude))

# Here's the function
result <- marineBackground(occs = occurrences, buff = 100000,
                           fraction = .9, partCount = 2, clipToOcean = FALSE)

Single raster plot

Description

A convenient wrapper around ggplot to generate a formatted plot of a single raster.

Usage

oneRasterPlot(
  rast,
  land = NA,
  landCol = "black",
  scaleRange = NA,
  graticule = TRUE,
  title = "A Raster",
  verbose = TRUE,
  ...
)

Arguments

Value

A plot of mapping the values of the input raster layer

See Also

viridis ggplot

Examples

library(terra)
rast <- rast(ncol=10, nrow=10)
values(rast) <- seq(0,99, 1)

oneRasterPlot(rast = rast)

Plotting 3D model in 2D

Description

This script plots a semitransparent layer of suitable habitat for each depth layer. The redder the color, the shallower the layer, the bluer, the deeper. The more saturated the color, the more layers with suitable habitat.

Usage

plotLayers(
  rast,
  land = NA,
  landCol = "black",
  title = NULL,
  graticule = TRUE,
  ...
)

Arguments

Value

A plot of class recordedplot

Note

Only include the depth layers that you actually want to plot.

See Also

viridis

Examples

library(terra)

rast1 <- rast(ncol=10, nrow=10)
values(rast1) <- rep(0:1, 50)

rast2 <- rast(ncol=10, nrow=10)
values(rast2) <- c(rep(0, 50), rep(1,50))

rast3 <- rast(ncol=10, nrow=10)
values(rast3) <- rep(c(1,0,0,1), 25)

distBrick <- c(rast1, rast2, rast3)

plotLayers(distBrick)

Comparative point mapping

Description

A convenient wrapper around ggplot to generate formatted plots comparing two sets of occurrence point plots.

Usage

pointCompMap(
  occs1,
  occs2,
  spName,
  land = NA,
  occs1Col = "#bd0026",
  occs2Col = "#fd8d3c",
  agreeCol = "black",
  occs1Name = "Set 1",
  occs2Name = "Set 2",
  landCol = "gray",
  waterCol = "steelblue",
  ptSize = 1,
  verbose = TRUE,
  ...
)

Arguments

Value

A ggplot plot object.

Note

The x and y column names of occs1 and occs2 must match.

See Also

ggplot

Examples

set.seed(5)
occs <- data.frame(cbind(decimalLatitude = sample(seq(7,35), 24),
                         decimalLongitude = sample(seq(-97, -70), 24)))

set.seed(0)
occs1 <- occs[sample(1:nrow(occs),
                     size = 12, replace = FALSE),]
set.seed(10)
occs2 <- occs[sample(1:nrow(occs),
                     size = 12, replace = FALSE),]

pointCompMap(occs1 = occs1, occs2 = occs2,
             occs1Col = "red", occs2Col = "orange",
             agreeCol = "purple",
             occs1Name = "2D",
             occs2Name = "3D",
             waterCol = "steelblue",
             spName = "Steindachneria argentea",
             ptSize = 2,
             verbose = FALSE)

Point mapping

Description

A convenient wrapper around ggplot to generate formatted occurrence point plots.

Usage

pointMap(
  occs,
  spName,
  land = NA,
  ptCol = "#bd0026",
  landCol = "gray",
  waterCol = "steelblue",
  ptSize = 1,
  verbose = TRUE,
  ...
)

Arguments

Value

A ggplot plot object.

See Also

ggplot

Examples

occs <- read.csv(system.file("extdata/Steindachneria_argentea.csv",
                             package='voluModel'))
spName <- "Steindachneria argentea"
pointMap(occs = occs, spName = spName,
         land = rnaturalearth::ne_countries(scale = "small",
                                            returnclass = "sf")[1])

Comparative raster mapping

Description

A convenient wrapper around terra::plot to generate formatted plots comparing two rasters. This is used in the context of voluModel to overlay semi-transparent distributions (coded as 1) in two different RasterLayers.

Usage

rasterComp(
  rast1 = NULL,
  rast2 = NULL,
  col1 = "#1b9e777F",
  col2 = "#7570b37F",
  rast1Name = "Set 1",
  rast2Name = "Set 2",
  land = NA,
  landCol = "black",
  title = "A Raster Comparison",
  graticule = TRUE,
  ...
)

Arguments

Value

A plot of class recordedplot overlaying mapped, semitransparent extents of the input rasters

Note

The extents of rast1 and rast2 must match.

See Also

plot

Examples

library(terra)
rast1 <- rast(ncol=10, nrow=10)
values(rast1) <- rep(0:1, 50)

rast2 <- rast(ncol=10, nrow=10)
values(rast2) <- c(rep(0, 50), rep(1,50))

rasterComp(rast1 = rast1, rast2 = rast2)

Smooth rasters

Description

Uses thin plate spline regression from fields package to smooth raster values.

Usage

smoothRaster(inputRaster, fast = FALSE, ...)

Arguments

Details

Original raster is smoothed using a thin plate spline. This may be desirable in cases where the user has a reasonable expectation of spatial autocorrelation, but observes putative measurement errors in a raster. The user has the option of choosing fastTps to speed calculation, but be advised that this is only an approximation of a true thin plate spline.

Value

An object of class SpatRaster

See Also

Tps, fastTps

Examples

library(terra)
library(fields)
# Create sample raster
r <- rast(ncol=100, nrow=100)
values(r) <- 1:10000

# Introduce a "bubble"
values(r)[720:725] <- 9999
plot(r)

# Smooth bubble with smoothRaster
fastSmooth <- smoothRaster(r, fast = TRUE, aRange = 10.0)
plot(fastSmooth)

Test Intersection

Description

Tests whether two rasters overlap. Used in ⁠\code{\link[voluModel:diversityStack]{diversityStack}}⁠ function to verify all rasters in list overlap with the template raster.

Usage

testIntersection(a, b)

Arguments

Value

A logical vector stating whether the two inputs overlap

Examples

library(terra)
rast1 <- rast(ncol=10, nrow=10)
values(rast1) <- rep(0:1, 50)

rast2 <- rast(ncol=10, nrow=10)
values(rast2) <- c(rep(0, 50), rep(1,50))

testIntersection(rast1, rast2)

rast1 <- crop(rast1, ext(10, 20, 30, 40))
rast2 <- crop(rast2, ext(-20, -10, -40, -30))

testIntersection(rast1, rast2)

Plot vertical sample

Description

Plots cell values along a vertical transect

Usage

transectPlot(
  rast = NULL,
  sampleAxis = "lon",
  axisValue = NA,
  scaleRange = NA,
  plotLegend = TRUE,
  depthLim = as.numeric(max(names(rast))),
  transRange = c(-90, 90),
  transTicks = 20,
  verbose = FALSE,
  ...
)

Arguments

Value

A ggplot showing a vertical slice through the SpatRaster.

Note

Only unprojected SpatRaster files are supported.

Examples

library(terra)

rast1 <- rast(ncol=10, nrow=10)
values(rast1) <- rep(0:3, 50)

rast2 <- rast(ncol=10, nrow=10)
values(rast2) <- c(rep(0, 50), rep(1,25), rep(2,25))

rast3 <- rast(ncol=10, nrow=10)
values(rast3) <- rep(c(1,3,2,1), 25)

distBrick <- c(rast1, rast2, rast3)
names(distBrick) <- c(0:2)

transectPlot(distBrick, depthLim = 3)

Transparent Color

Description

Generates transparent colors

Usage

transpColor(color, percent = 50)

Arguments

Value

A character string with hex color, including adjustment for transparency.

Examples

transpColor(color = "red", percent = 50)

Vertical sample

Description

Samples data along a vertical transect

Usage

verticalSample(x = NULL, sampleAxis = "lon", axisValue = NA)

Arguments

Value

A data.frame with values sampled across vertical transect.

Note

Only unprojected SpatRaster files are supported.

Sampling from a SpatRaster vector using 3D coordinates

Description

Gets values at x,y,z occurrences from a given 3D environmental variable brick

Usage

xyzSample(occs, envBrick, verbose = TRUE)

Arguments

Details

The SpatRaster vector object should have numeric names that correspond with the beginning depth of a particular depth slice. For example, one might have three layers, one from 0 to 10m, one from 10 to 30m, and one from 30 to 100m. You would name the layers in this brick ⁠names(envBrick) <- c(0, 10, 30⁠. xyzSample identifies the layer name that is closest to the depth layer value at a particular X, Y coordinate, and samples the environmental value at that 3D coordinate.

Value

Vector of environmental values equal in length to number of rows of input occs data.frame.

Examples

library(terra)

# Create test raster
r1 <- rast(ncol=10, nrow=10)
values(r1) <- 1:100
r2 <- rast(ncol=10, nrow=10)
values(r2) <- c(rep(20, times = 50), rep(60, times = 50))
r3 <- rast(ncol=10, nrow=10)
values(r3) <- 8
envBrick <- c(r1, r2, r3)
names(envBrick) <- c(0, 10, 30)

# Create test occurrences
set.seed(0)
longitude <- sample(ext(envBrick)[1]:ext(envBrick)[2],
                    size = 10, replace = FALSE)
set.seed(0)
latitude <- sample(ext(envBrick)[3]:ext(envBrick)[4],
                   size = 10, replace = FALSE)
set.seed(0)
depth <- sample(0:35, size = 10, replace = TRUE)
occurrences <- as.data.frame(cbind(longitude,latitude,depth))

# Test function
occSample3d <- xyzSample(occurrences, envBrick)

# How to use
occurrences$envtValue <- occSample3d