inst/doc/internal-cell-representation.R

In a5R: 'A5' Discrete Global Grid System

## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## -----------------------------------------------------------------------------
library(a5R)
cell <- a5_lonlat_to_cell(-3.19, 55.95, resolution = 10)
vctrs::field(cell, "b1")
vctrs::field(cell, "b8")

## -----------------------------------------------------------------------------
# Display calls format(), which converts to hex for readability
cell

# Explicit conversion
a5_u64_to_hex(cell)

# Round-trip from hex
a5_cell("0800000000000006")

## -----------------------------------------------------------------------------
set.seed(42)
cells <- a5_lonlat_to_cell(
  runif(1e6, -180, 180),
  runif(1e6, -80, 80),
  resolution = 10
)

# rcrd: eight contiguous raw vectors (8 × 1 byte × 1M ≈ 7.6 MB)
format(object.size(cells), units = "MB")

# equivalent hex strings would be ~81 MB
# (16 chars + 56-byte SEXP header per string)
hex <- a5_u64_to_hex(cells)
format(object.size(hex), units = "MB")

## -----------------------------------------------------------------------------
cells_with_na <- a5_cell(c("0800000000000006", NA))
is.na(cells_with_na)