Results, output, and visualization

library(priogridR)

The conversion functions can return ordinary data frames, rasters, or a structured pg_result. The workflow helpers make it easier to organize, inspect, save, and visualize those outputs consistently.

Reproducible project paths

pg_paths() constructs conventional raw, processed, and temporary data paths without changing the working directory.

project_root <- file.path(tempdir(), "priogridR-vignette-project")
paths <- pg_paths(project_root, create = TRUE)
paths
#> $root
#> [1] "/tmp/Rtmp4Nw49W/priogridR-vignette-project"
#> 
#> $raw
#> [1] "/tmp/Rtmp4Nw49W/priogridR-vignette-project/data/raw"
#> 
#> $processed
#> [1] "/tmp/Rtmp4Nw49W/priogridR-vignette-project/data/processed"
#> 
#> $temporary
#> [1] "/tmp/Rtmp4Nw49W/priogridR-vignette-project/data/temp"

The returned list can be passed directly to file.path() when creating input or output filenames.

Structured conversion results

Request return = "result" when both the converted data and its metadata are useful.

events <- data.frame(
  longitude = c(10, 10.1, 20),
  latitude = c(50, 50.1, 60)
)

config <- priogrid::pg_config(nrow = 18, ncol = 36, verbose = FALSE)

event_result <- pg_from_points(
  events,
  variable = "event_count",
  longitude = "longitude",
  latitude = "latitude",
  aggregation = "count",
  return = "result",
  config = config
)

event_result
#> <pg_result>
#>   Rows: 3
#>   Raster layers: 1
#>   Variable: event_count

The ordinary tabular representation is available through as.data.frame().

event_data <- as.data.frame(event_result)
head(event_data)
#>   pgid event_count
#> 1  488           1
#> 2  524           1
#> 3  525           1

Write outputs

pg_write_result() selects the writer from the filename extension. Data frames and tabular pg_result objects support CSV, RDS, and—when arrow is installed—Parquet. Rasters support TIFF and VRT.

csv_file <- file.path(paths$temporary, "event-counts.csv")
pg_write_result(event_result, csv_file, overwrite = TRUE)
utils::read.csv(csv_file)
#>   pgid event_count
#> 1  488           1
#> 2  524           1
#> 3  525           1

Use explicit overwrite permission in reproducible scripts when replacing an earlier output is intended.

pg_write_result(raster_result, "data/processed/variable.tif", overwrite = TRUE)

Plot grid data

pg_plot() joins a variable to configured cell polygons and returns an ordinary ggplot2 object.

map <- pg_plot(event_data, "event_count", config = config)
map

Add layers or replace theme components as with any other ggplot. pg_theme() can also be used independently.

map +
  ggplot2::labs(title = "Example event counts") +
  pg_theme(legend.position = "bottom")

Temporary example files are removed when the R session ends. In a real project, use a persistent project root and keep raw and processed data in separate directories.