The change in water occurrence intensity between the two periods is derived
from homologous pairs of months (i.e. same months containing valid
observations in both periods). The difference in the occurrence of surface
water was calculated for each homologous pair of months. The average of all
of these differences constitutes the Surface Water Occurrence change
intensity. The raster files have integer cell values between [0, 200]
where 0 represents surface water loss and 200 represents surface water gain.
Arguments
- engine
The preferred processing functions from either one of "zonal", "extract" or "exactextract". Default: "extract".
- stats
Aggregation function with which the data are combined. Default: "mean".
Details
The pixel values are aggregated using method provided via the
stats parameter using the specified engine.
The required resources for this indicator are:
Examples
# \dontshow{
mapme.biodiversity:::.copy_resource_dir(file.path(tempdir(), "mapme-data"))
# }
# \dontrun{
library(sf)
library(mapme.biodiversity)
outdir <- file.path(tempdir(), "mapme-data")
dir.create(outdir, showWarnings = FALSE)
mapme_options(
outdir = outdir,
verbose = FALSE
)
aoi <- system.file("extdata", "shell_beach_protected_area_41057_B.gpkg",
package = "mapme.biodiversity"
) %>%
read_sf() %>%
get_resources(get_global_surface_water_change()) %>%
calc_indicators(
calc_gsw_change(engine = "extract", stats = "mean")
) %>%
portfolio_long()
aoi
#> Simple feature collection with 1 feature and 10 fields
#> Geometry type: POLYGON
#> Dimension: XY
#> Bounding box: xmin: -59.84866 ymin: 8.307999 xmax: -59.71 ymax: 8.364002
#> Geodetic CRS: WGS 84
#> # A tibble: 1 × 11
#> WDPAID NAME DESIG_ENG ISO3 assetid indicator datetime variable unit value
#> <dbl> <chr> <chr> <chr> <int> <chr> <date> <chr> <chr> <dbl>
#> 1 41057 Shel… Managed … GUY 1 gsw_chan… 2021-01-01 gsw_cha… unit… 100
#> # ℹ 1 more variable: geom <POLYGON [°]>
# }