sedona_spatial_join_count_by_key {apache.sedona} R Documentation

## Perform a spatial count-by-key operation based on two Sedona spatial RDDs.

### Description

For each element p from 'spatial_rdd', count the number of unique elements q from 'query_window_rdd' such that (p, q) satisfies the spatial relation specified by 'join_type'.

### Usage

sedona_spatial_join_count_by_key(
spatial_rdd,
query_window_rdd,
join_type = c("contain", "intersect"),
)


### Arguments

 spatial_rdd Spatial RDD containing geometries to be queried. query_window_rdd Spatial RDD containing the query window(s). join_type Type of the join query (must be either "contain" or "intersect"). If 'join_type' is "contain", then a geometry from 'spatial_rdd' will match a geometry from the 'query_window_rdd' if and only if the former is fully contained in the latter. If 'join_type' is "intersect", then a geometry from 'spatial_rdd' will match a geometry from the 'query_window_rdd' if and only if the former intersects the latter. partitioner Spatial partitioning to apply to both 'spatial_rdd' and 'query_window_rdd' to facilitate the join query. Can be either a grid type (currently "quadtree" and "kdbtree" are supported) or a custom spatial partitioner object. If 'partitioner' is NULL, then assume the same spatial partitioner has been applied to both 'spatial_rdd' and 'query_window_rdd' already and skip the partitioning step. index_type Controls how 'spatial_rdd' and 'query_window_rdd' will be indexed (unless they are indexed already). If "NONE", then no index will be constructed and matching geometries will be identified in a doubly nested- loop iterating through all possible pairs of elements from 'spatial_rdd' and 'query_window_rdd', which will be inefficient for large data sets.

### Value

A spatial RDD containing the join-count-by-key results.

Other Sedona spatial join operator: sedona_spatial_join()

### Examples

library(sparklyr)
library(apache.sedona)

sc <- spark_connect(master = "spark://HOST:PORT")

if (!inherits(sc, "test_connection")) {
input_location <- "/dev/null" # replace it with the path to your input file
sc,
location = input_location,
delimiter = ",",
type = "point",
first_spatial_col_index = 1L
)
query_rdd_input_location <- "/dev/null" # replace it with the path to your input file
sc,
location = query_rdd_input_location,
type = "polygon"
)
join_result_rdd <- sedona_spatial_join_count_by_key(
rdd,
query_rdd,
join_type = "intersect",