Extract zonal mean time series for an AOI

For each variable and period in the catalog, crops the COG to the AOI and computes the spatial mean per year (band). Returns a tidy tibble of raw climate values suitable for cd_baseline(), cd_anomaly(), or cd_trend().

Usage

cd_extract(
  catalog,
  aoi,
  variables = catalog$variable,
  periods = catalog$period,
  years = NULL
)

Arguments

catalog

A tibble from cd_catalog() with columns variable, period, href.

aoi

An sf or SpatVector polygon.

variables

Character vector of variables to extract. Defaults to all variables in catalog.

periods

Character vector of periods to extract. Defaults to all periods in catalog.

years

Optional integer vector to filter specific years.

Value

A tibble with columns:

variable

Climate variable short name.

period

Temporal aggregation period.

year

Year (integer).

value

Spatial mean of the climate value for this AOI.

Examples

catalog <- cd_catalog(
  system.file("extdata", "example_catalog.json", package = "cd")
)
aoi <- sf::st_read(
  system.file("extdata", "example_aoi.gpkg", package = "cd"),
  quiet = TRUE
)
cd_extract(catalog, aoi)
#> # A tibble: 10 × 4
#>    variable period  year  value
#>    <chr>    <chr>  <int>  <dbl>
#>  1 tmean    annual  1951 -2.87 
#>  2 tmean    annual  1952 -2.01 
#>  3 tmean    annual  1953 -0.881
#>  4 tmean    annual  1954 -0.223
#>  5 tmean    annual  1955 -1.22 
#>  6 tmean    annual  1956 -2.88 
#>  7 tmean    annual  1957 -1.37 
#>  8 tmean    annual  1958 -1.34 
#>  9 tmean    annual  1959  0.537
#> 10 tmean    annual  1960 -1.61