butterfly.Rd
Identify butterflies from a VoxelSpace
object.
A butterfly refers to a non-empty isolated voxel. Non-empty means that there is one or more hits recorded in the voxel. Isolated means that voxels in the Moore neighborhood of rank 1 are empty (no hit).
butterfly(vxsp)
a VoxelSpace
object
a list of voxel index (i, j, k) identified as butterfly.
# load a voxel file
vxsp <- readVoxelSpace(system.file("extdata", "tls_sample.vox", package = "AMAPVox"))
# identify butterflies
btf <- butterfly(vxsp)
# clear butterflies
clear(vxsp, butterfly(vxsp))