aggregate.R created

[Snafkin547]

Description

The aggregate function, created using exactextractr, enables the aggregation (sum and average) of previously downscaled carbon flux output from the NA_downscale function. Users can aggregate data for spatial areas of their choice by providing appropriate polygon data.

Motivation and Context

This change is required to enable the aggregation of downscaled carbon flux data to user-specified spatial units. It solves the problem of needing to summarize large-scale raster data into meaningful aggregated values (sum and average) for specific areas, aiding in spatial analysis and decision-making.

Review Time Estimate

• [ ] Immediately
• [x] Within one week
• [ ] When possible

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My change requires a change to the documentation.
• [ ] My name is in the list of CITATION.cff
• [ ] I have updated the CHANGELOG.md.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.

[Snafkin547]

You can run this function in this way:

Download a shapefile of U.S. states (if not already available)

url <- "https://www2.census.gov/geo/tiger/GENZ2020/shp/cb_2020_us_state_20m.zip"
download.file(url, destfile = "polygon/us_states.zip")
unzip("polygon/us_states.zip", exdir = "polygon/us_states")

Load the shapefile

us_states <- st_read("polygon/us_states/cb_2020_us_state_20m.shp")
saveRDS(us_states, "polygon/polygon_us_states.rds")

Load the downscale_output list

downscale_output <- readRDS("path/to/your raster file")

read_raster <- function(file_path) {
  rast(file_path)
}

downscale_output$maps <- lapply(downscale_output$maps, read_raster)
us_states <- readRDS("polygon/us_states.rds")
state = "MA"
polygon_data <- st_transform(us_states[us_states$STUSPS == state, ], crs = "EPSG:4326")

massachusetts <- aggregate_by_state(downscale_output, polygon_data)

print(massachusetts)
plot(st_geometry(massachusetts))