Annulus matrix
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 annulus.matrix(5, 3) # 5 concentric rings with the 3 inner set to 0 annulus.matrix(5, 3, null.value=NA) # 5 concentric rings with the 3 inner set to NA annulus.matrix(5, 3, 5) # 5 rings with 3 inner and 5 outer set to 0 annulus.matrix(9, 3, 7) # 9 rings with 3 inner and 7 outer set to 0
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