Get the position of an H3 cell within its parent — ddbh3_get_child

Get the position of H3 cell indexes stored as strings or unsigned 64-bit integers (UBIGINT) within their parent cell at a specified resolution. The position is a zero-based index among all children of the parent cell.

Usage

ddbh3_get_child_pos(
  x,
  resolution = 8,
  h3 = "h3string",
  new_column = "h3child_pos",
  conn = NULL,
  name = NULL,
  overwrite = FALSE,
  quiet = FALSE
)

Arguments

x

Input data. One of:

duckspatial_df: A lazy spatial data frame via dbplyr.
sf: A spatial data frame.
tbl_lazy: A lazy data frame from dbplyr.
data.frame: A standard R data frame.
character string: A table or view name in conn.
character vector: A vector of values to operate on in vectorized mode (requires conn = NULL).

resolution

A number specifying the resolution level of the H3 string (between 0 and 15)

h3

The name of a column in x containing the H3 strings or H3 unsigned 64-bit integers (UBIGINT)

new_column

Name of the new column to create on the input data. If NULL, the function will return a vector with the result

conn

A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.

name

A character string of length one specifying the name of the table, or a character string of length two specifying the schema and table names. If NULL (the default), the function returns the result as an sf object

overwrite

Boolean. whether to overwrite the existing table if it exists. Defaults to FALSE. This argument is ignored when name is NULL.

quiet

A logical value. If TRUE, suppresses any informational messages. Defaults to FALSE.

Value

One of the following, depending on the inputs:

tbl_lazy: If x is not spatial.
duckspatial_df: If x is spatial (e.g. an sf or duckspatial_df object).
TRUE (invisibly): If name is provided, a table is created in the connection and TRUE is returned invisibly.
vector: If x is a character vector and conn = NULL, the function operates in vectorized mode, returning a vector of the same length as x.

Examples

## Load needed packages
library(duckh3)
library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union

## Setup the default connection with h3 and spatial extensions
## This is a mandatory step to use duckh3 functions
ddbh3_default_conn(threads = 1)

## Load example data
points_tbl <- read.csv(
  system.file("extdata/example_pts.csv", package = "duckh3")
)

## Add H3 string column
points_tbl <- ddbh3_lonlat_to_h3(points_tbl, resolution = 6)

## Get position relative to resolution 4
ddbh3_get_child_pos(points_tbl, resolution = 4)
#> # Source:   table<temp_view_07af1fc2_8d65_4772_abfb_cbaa6c967845> [?? x 7]
#> # Database: DuckDB 1.5.2 [unknown@Linux 6.17.0-1010-azure:R 4.6.0/:memory:]
#>        X    id    lat    lon category h3string        h3child_pos
#>    <int> <int>  <dbl>  <dbl> <chr>    <chr>               <int64>
#>  1     1     1 -43.1   16.2  B        86d02dcc7ffffff          21
#>  2     2     2  29.2   61.9  C        864221ac7ffffff          21
#>  3     3     3 -20.7   51.3  C        86a20e8f7ffffff          27
#>  4     4     4  50.9  -14.0  B        86181c6cfffffff          22
#>  5     5     5 -57.6    8.71 C        86e6cece7ffffff          25
#>  6     6     6 -56.2   21.5  B        86e69d237ffffff           6
#>  7     7     7 -33.7  -17.0  C        86c188077ffffff          13
#>  8     8     8 -32.7  -31.9  A        86c52b36fffffff          40
#>  9     9     9  -7.39  39.0  C        867b6b577ffffff          41
#> 10    10    10  10.0  -89.9  A        866d424afffffff          19
#> # ℹ more rows