Given a grid object (Grid1d, Grid2d or Grid3d) and an index of each cell point in the grid obtained by getCell(), it returns a dataframe with coordinates and counts for each cell. According to the "by" parameter of the grid, the coordinates will be sorted with x or z increasing faster.
Value
A dataframe with grid coordinates and and the count of how many points fall within each cell of the grid
Examples
# 1. Generate random points on a plane
df_points <- data.frame(
x = c(rnorm(n = 50000, mean = -2), rnorm(n = 50000, mean = 2)),
y = c(rnorm(n = 50000, mean = 1), rnorm(n = 50000, mean = -1))
)
# 2. Define a grid that contains all the points generated
the_grid <- makeGrid2d(
xmin = floor(min(df_points$x)), ymin = floor(min(df_points$y)),
xmax = ceiling(max(df_points$x)), ymax = ceiling(max(df_points$y)),
xcell = 50, ycell = 50, by = "v"
)
# 3. Match each point with a grid element
grid_index <- getCell(the_grid, df_points)
# 4. Count how many points there are in each element of the grid
df_grid <- getCounts(the_grid, grid_index)
head(df_grid)
#> x y counts
#> 1 -6.86 -5.88 0
#> 2 -6.86 -5.64 0
#> 3 -6.86 -5.40 0
#> 4 -6.86 -5.16 0
#> 5 -6.86 -4.92 0
#> 6 -6.86 -4.68 0