Divides a two-dimensional cloud of points in blocks according to a user-defined number of rows and columns. This is applied to the element master_matrix and, if not NULL, to preselected_sites.
Usage
make_blocks(master_matrix, variable_1, variable_2, n_cols, n_rows = NULL,
block_type = "equal_area")Arguments
- master_matrix
object derived from function
prepare_master_matrix.- variable_1
(character or numeric) name or position of the first variable (x-axis) to be used to create blocks.
- variable_2
(character or numeric) name or position of the second variable (y-axis) to be used to create blocks (must be different from the first one).
- n_cols
(numeric) number of columns of a grid used to creates blocks and split the bi-dimensional space.
- n_rows
(numeric) number of rows of a grid used to creates blocks and split the bi-dimensional space. If NULL, the default,
n_rows = n_cols.- block_type
(character) type of blocks to be use for dividing the bi-dimensional space. Two options are available: "equal_area" and "equal_points". Default = "equal_area".
Value
An S3 object of class master_matrix, containing the same elements found in a master_matrix object, with an additional column on the master_matrix data.frame containing block identifiers. If the element preselected_sites is not NULL in master_matrix, blocks are also assigned to this sites.
Details
For block_type, option "equal_area" generates blocks of the same size. The other option ("equal_points"), generates blocks containing the same number of points, which generally results in blocks of different sizes.
Examples
# Data
m_matrix <- read_master(system.file("extdata/m_matrix.rds",
package = "biosurvey"))
# Creating blocks
m_blocks <- make_blocks(m_matrix, variable_1 = "PC1",
variable_2 = "PC2", n_cols = 10, n_rows = 10,
block_type = "equal_area")
unique(m_blocks$data_matrix$Block)
#> [1] 5 4 2 23 24 1 6 3 25 7 26 27 8 35 28 36 37 38 29
#> [20] 34 39 47 30 48 40 41 46 49 59 60 70 72 71 58 50 62 61 51
#> [39] 73 63 84 57 85 95 52 75 42 45 31 9 32 82 94 83 81 69 96
#> [58] 74 107 106 93 105 117 118 56