Creates a square matrix representing annulus position values of 1 and defined null
annulus.matrix(scale = 3, inner.scale = 0, outer.scale = 0, null.value = 0)
| scale | Number of rings (defines dimensions of matrix) |
|---|---|
| inner.scale | Number of inner rings to set to null.value |
| outer.scale | Number of outer rings to set to null.value |
| null.value | Value to set inner and outer scale(s) to |
A matrix object with defined null.value and 1, representing retained rings
This function will return a matrix of 1 and defined null.value based on a specification of the scale, inner scale and outer scale. The scale defines how many rings will be represented in the matrix based on (2 * scale - 1). So, a scale of 3 will result in a 5x5 matrix. The inner.scale and outer.scale arguments represent the > and < rings that will be set to the defined null.value (see examples). The resulting matrix can be used as the specified window in a focal function.
Jeffrey S. Evans <jeffrey_evans@tnc.org>
annulus.matrix(5) # 5 concentric rings#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] #> [1,] 1 1 1 1 1 1 1 1 1 #> [2,] 1 1 1 1 1 1 1 1 1 #> [3,] 1 1 1 1 1 1 1 1 1 #> [4,] 1 1 1 1 1 1 1 1 1 #> [5,] 1 1 1 1 0 1 1 1 1 #> [6,] 1 1 1 1 1 1 1 1 1 #> [7,] 1 1 1 1 1 1 1 1 1 #> [8,] 1 1 1 1 1 1 1 1 1 #> [9,] 1 1 1 1 1 1 1 1 1annulus.matrix(5, 3) # 5 concentric rings with the 3 inner set to 0#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] #> [1,] 1 1 1 1 1 1 1 1 1 #> [2,] 1 1 1 1 1 1 1 1 1 #> [3,] 1 1 0 0 0 0 0 1 1 #> [4,] 1 1 0 0 0 0 0 1 1 #> [5,] 1 1 0 0 0 0 0 1 1 #> [6,] 1 1 0 0 0 0 0 1 1 #> [7,] 1 1 0 0 0 0 0 1 1 #> [8,] 1 1 1 1 1 1 1 1 1 #> [9,] 1 1 1 1 1 1 1 1 1annulus.matrix(5, 3, null.value=NA) # 5 concentric rings with the 3 inner set to NA#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] #> [1,] 1 1 1 1 1 1 1 1 1 #> [2,] 1 1 1 1 1 1 1 1 1 #> [3,] 1 1 NA NA NA NA NA 1 1 #> [4,] 1 1 NA NA NA NA NA 1 1 #> [5,] 1 1 NA NA NA NA NA 1 1 #> [6,] 1 1 NA NA NA NA NA 1 1 #> [7,] 1 1 NA NA NA NA NA 1 1 #> [8,] 1 1 1 1 1 1 1 1 1 #> [9,] 1 1 1 1 1 1 1 1 1annulus.matrix(5, 3, 5) # 5 rings with 3 inner and 5 outer set to 0#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] #> [1,] 0 0 0 0 0 0 0 0 0 #> [2,] 0 1 1 1 1 1 1 1 0 #> [3,] 0 1 0 0 0 0 0 1 0 #> [4,] 0 1 0 0 0 0 0 1 0 #> [5,] 0 1 0 0 0 0 0 1 0 #> [6,] 0 1 0 0 0 0 0 1 0 #> [7,] 0 1 0 0 0 0 0 1 0 #> [8,] 0 1 1 1 1 1 1 1 0 #> [9,] 0 0 0 0 0 0 0 0 0annulus.matrix(9, 3, 7) # 9 rings with 3 inner and 7 outer set to 0#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] #> [1,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [2,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [3,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [4,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [5,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [6,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [7,] 0 0 0 1 1 1 0 0 0 0 0 1 1 #> [8,] 0 0 0 1 1 1 0 0 0 0 0 1 1 #> [9,] 0 0 0 1 1 1 0 0 0 0 0 1 1 #> [10,] 0 0 0 1 1 1 0 0 0 0 0 1 1 #> [11,] 0 0 0 1 1 1 0 0 0 0 0 1 1 #> [12,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [13,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [14,] 0 0 0 1 1 1 1 1 1 1 1 1 1 #> [15,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [16,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [17,] 0 0 0 0 0 0 0 0 0 0 0 0 0 #> [,14] [,15] [,16] [,17] #> [1,] 0 0 0 0 #> [2,] 0 0 0 0 #> [3,] 0 0 0 0 #> [4,] 1 0 0 0 #> [5,] 1 0 0 0 #> [6,] 1 0 0 0 #> [7,] 1 0 0 0 #> [8,] 1 0 0 0 #> [9,] 1 0 0 0 #> [10,] 1 0 0 0 #> [11,] 1 0 0 0 #> [12,] 1 0 0 0 #> [13,] 1 0 0 0 #> [14,] 1 0 0 0 #> [15,] 0 0 0 0 #> [16,] 0 0 0 0 #> [17,] 0 0 0 0