README.md

In paulhegedus/SampleBuilder: Functions for building sampling designs

SampleBuilder

Paul Hegedus

The goal of SampleBuilder is to help in generating sampling designs. SampleBuilder has functions for building transects, gridded systematic points, and random points.

Installation

You can install the most up to date version of SampleBuilder from GitHub with:

# install.packages("devtools")
devtools::install_github("paulhegedus/SampleBuilder")

Make Transects Example

This is a basic example which shows you how to build transects for a line layer:

library(SampleBuilder)

## Make Transects
t_lines <- make_transects(
  line_layer_path = "/Path/To/The/Line/Layer/Filename.shp",
  t_number = 10, # 10 transects
  t_length = 1000, # l000m transect length
  t_size = 10, # 10m x 10m transect cells
  buddy_t = TRUE, # each transect has a buddy
  direction = "positive", # transects only built to the N or W of line layer
  allow_overlaps = FALSE # overlaps of transects are allowed
)

## Make Points along Transects
t_pts <- make_transect_pts(t_lines, 1000, 10)

## Create Sampling Info - data.frame with 'name', 'type', and 'default' cols
sampling_info <- data.frame(
  name = c("date", "observer", "comment1", "comment2", "comment3", "comment4", "comment5"),
  type = rep("character", 7),
  default = rep(NA, 7)
)

## Add Sampling Information to File
t_lines_wInfo <- add_info(t_lines, sampling_info)
t_pts_wInfo <- add_info(t_pts, sampling_info)

## Save Transect Lines and Points
sf::st_write(t_lines_wInfo, "/Path/To/Save/Location/And/Filename.shp")
sf::st_write(t_pts_wInfo, "/Path/To/Save/Location/And/Filename.shp")

**Figure 1.** Example of 10 1km transects only in the positive direction. Each of the 5 transects visible have a buddy transect that is between 1 and 3 transect widths from the other for efficient sampling.

Make Grid Example

This is a basic example of how to build a gridded sampling design for an area:

library(SampleBuilder)

## Make Grid
grid_dat <- make_grid(poly_layer_path = "/Path/To/The/Poly/Layer/Filename.shp",
                      cell_size = 61) # in meters (~200 feet)

## Get Centroids of grid
grid_centroids <- get_centroids(grid_dat)

## Create Sampling Info - data.frame with 'name', 'type', and 'default' cols
sampling_info <- data.frame(
  name = c("date", "observer", "comment1", "comment2", "comment3", "comment4", "comment5"),
  type = rep("character", 7),
  default = rep(NA, 7)
)

## Add Sampling Information to File
grid_pts_wInfo <- add_info(grid_centroids, sampling_info)

## Save Grid and Points
sf::st_write(grid_dat, "/Path/To/Save/Location/And/Filename.shp")
sf::st_write(grid_pts_wInfo, "/Path/To/Save/Location/And/Filename.shp")

**Figure 2.** Example of 200 foot grid cells with centroid locations for sampling.

Make Random Points Example

This is a basic example of how to build random points across an area:

library(SampleBuilder)

## Get Area Boundary
poly_dat <- get_data("/Path/To/The/Poly/Layer/Filename.shp")

## Get Random Samples across Polygon
rand_pts <- sp::spsample(x = as(poly_dat, "Spatial"), 
                         n = 18,  
                         type = "random") %>% 
  sf::st_as_sf()

## Create Sampling Info - data.frame with 'name', 'type', and 'default' cols
sampling_info <- data.frame(
  name = c("date", "observer", "comment1", "comment2", "comment3", "comment4", "comment5"),
  type = rep("character", 7),
  default = rep(NA, 7)
)

## Add Sampling Information to File
rand_pts_wInfo <- add_info(rand_pts, sampling_info)

## Save Transect Lines and Points
sf::st_write(rand_pts_wInfo, "/Path/To/Save/Location/And/Filename.shp")

**Figure 3.** Example of random point sampling (note that SampleBuilder not really needed).

paulhegedus/SampleBuilder documentation built on July 21, 2023, 9:35 a.m.