Calculate elevation statistics

This function allows to calculate elevation statistics for polygons. For each polygon, the desired statistic(s) are returned.

Usage

calc_elevation(engine = "extract", stats = "mean")

Arguments

engine

The preferred processing functions from either one of "zonal", "extract" or "exactextract" as character.

stats

Function to be applied to compute statistics for polygons either one or multiple inputs as character "mean", "median" or "sd".

Value

A function that returns an indicator tibble with specified elevation statistics as variable and corresponding values (in meters) as value.

Details

The required resources for this indicator are:

• nasa_srtm

Examples

# \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", "sierra_de_neiba_478140_2.gpkg",
  package = "mapme.biodiversity"
) %>%
  read_sf() %>%
  get_resources(get_nasa_srtm()) %>%
  calc_indicators(
    calc_elevation(engine = "extract", stats = c("mean", "median", "sd", "var"))
  ) %>%
  portfolio_long()

aoi
#> Simple feature collection with 4 features and 8 fields
#> Geometry type: POLYGON
#> Dimension:     XY
#> Bounding box:  xmin: -71.80933 ymin: 18.57668 xmax: -71.33201 ymax: 18.69931
#> Geodetic CRS:  WGS 84
#> # A tibble: 4 × 9
#>   WDPAID ISO3  assetid indicator datetime            variable       unit   value
#>    <dbl> <chr>   <int> <chr>     <dttm>              <chr>          <chr>  <dbl>
#> 1 478140 DOM         1 elevation 2000-02-01 00:00:00 elevation_mean m      1704.
#> 2 478140 DOM         1 elevation 2000-02-01 00:00:00 elevation_med… m      1702 
#> 3 478140 DOM         1 elevation 2000-02-01 00:00:00 elevation_sd   m       219.
#> 4 478140 DOM         1 elevation 2000-02-01 00:00:00 elevation_var  m     48085.
#> # ℹ 1 more variable: geom <POLYGON [°]>
# }