grid_to_index-methods: Generic function to convert N-dimensional grid coordinates to...

In bbuchsbaum/neuroim2: Data Structures for Brain Imaging Data

Generic function to convert N-dimensional grid coordinates to 1D indices

Description

Converts 2D grid coordinates to linear indices for a NeuroSlice object.

Usage

grid_to_index(x, coords)

## S4 method for signature 'NeuroSlice,matrix'
grid_to_index(x, coords)

## S4 method for signature 'NeuroSlice,numeric'
grid_to_index(x, coords)

## S4 method for signature 'NeuroSpace,matrix'
grid_to_index(x, coords)

## S4 method for signature 'NeuroSpace,numeric'
grid_to_index(x, coords)

## S4 method for signature 'NeuroVol,matrix'
grid_to_index(x, coords)

## S4 method for signature 'NeuroVol,numeric'
grid_to_index(x, coords)

Arguments

x	A NeuroSlice object
coords	Either a numeric vector of length 2 or a matrix with 2 columns, representing (x,y) coordinates in the slice grid

Details

Convert Grid Coordinates to Linear Indices

Value

An integer vector of 1D indices corresponding to coords.

See Also

index_to_grid for the inverse operation

Examples

# Create a 2D space (10x10)
space_2d <- NeuroSpace(c(10,10), c(1,1))

# Convert 2D grid coordinates to linear indices
coords_2d <- matrix(c(1,1, 2,2), ncol=2, byrow=TRUE)
idx_2d <- grid_to_index(space_2d, coords_2d)
# First coordinate (1,1) maps to index 1
# Second coordinate (2,2) maps to index 12 (= 2 + (2-1)*10)

# Create a 3D space (10x10x10)
space_3d <- NeuroSpace(c(10,10,10), c(1,1,1))

# Convert 3D grid coordinates to linear indices
coords_3d <- matrix(c(1,1,1, 2,2,2), ncol=3, byrow=TRUE)
idx_3d <- grid_to_index(space_3d, coords_3d)

# Single coordinate can also be converted
idx <- grid_to_index(space_3d, c(1,1,1))

slice_space <- NeuroSpace(c(10, 10))
slice_data <- matrix(1:100, 10, 10)
slice <- NeuroSlice(slice_data, slice_space)

# Convert single coordinate
idx <- grid_to_index(slice, c(5, 5))

# Convert multiple coordinates
coords <- matrix(c(1,1, 2,2, 3,3), ncol=2, byrow=TRUE)
indices <- grid_to_index(slice, coords)

bbuchsbaum/neuroim2 documentation built on Feb. 26, 2025, 3:49 p.m.