geo.groupByArea() function

geo.groupByArea() groups rows by geographic area.

Area sizes are determined by the specified level. Each geographic area is assigned a unique identifier (the S2 cell ID token) which is stored in the newColumn. Results are grouped by newColumn.

Function type signature

(
    <-tables: stream[{A with s2_cell_id: string, lon: float, lat: float}],
    level: int,
    newColumn: string,
    ?s2cellIDLevel: int,
) => stream[B] where B: Record

Parameters

newColumn

(Required) Name of the new column for the unique identifier for each geographic area.

level

(Required) S2 Cell level used to determine the size of each geographic area.

s2cellIDLevel

S2 Cell level used in the s2_cell_id tag. Default is -1 (detects S2 cell level from the s2_cell_id tag).

tables

Input data. Default is piped-forward data (<-).

Examples

Group geotemporal data by geographic area

import "experimental/geo"

data
    |> geo.groupByArea(newColumn: "foo", level: 4)