spatial_link_index: Spatial index distance matrix

In czigler/arepa: An R Package for EPA data retrieving and processing

Description

Spatial index distance matrix

Usage

spatial_link_index(data1, lat1, lon1, id1, data2, lat2, lon2, id2,
  within = NULL, closest = FALSE)

Arguments

data1	Dataset 1
lat1	Latitude variable in dataset 1
lon1	Longitude variable in dataset 1
id1	Unique key in dataset 1
data2	Dataset 1
lat2	Latitude variable in dataset 2
lon2	Longitude variable in dataset 2
id2	Unique key in dataset 2
within	Link within kilometers
closest	Closest within Boolean (unique key is id2, so typically zip code)

Value

This function returns a data table of pairwise distances within kilometers with column names id1, id2 and Distance.

Examples

years <- 2000:2002 # possible range 1990-2018
within_km <- 9.656 # 6 miles
parameter_code <- 81102 # for PM 10
##----- Get PM10 annual data and set unique Monitor key
# Download AQS data in Data_AQS/all.
# get_AQS_data_annual(years)
PM <- load_annual_average(years)
PM <- subset(PM, Parameter.Code == parameter_code)
##----- Zip codes
ZIP <- get_zip_codes()
##----- Spatial index to join monitors and Zip codes.  May take a couple of minutes
Link_PM_Zip_Index <- spatial_link_index(PM, "Latitude", "Longitude", "Monitor",
                                        ZIP, "Latitude.zip", "Longitude.zip", "zip",
                                        within = within_km) 

czigler/arepa documentation built on Oct. 2, 2020, 7:38 p.m.