Extract ecoregion name and ID from [Ecoregions of the World](https://www.worldwildlife.org/publications/terrestrial-ecoregions-of-the-world). Olson et al. 2001 [(BioScience)](https://academic.oup.com/bioscience/article/51/11/933/227116).
Computation was performed in EVE HPC cluster using function `A98_PredictorsExtract.R`. Divided in 99 chunks.
```{r eval=F}
...
...
@@ -470,15 +470,17 @@ Summarize:
```{r message=F, echo=F}
knitr::kable(header %>%
group_by(Ecoregion) %>%
summarize(num.plot=n()),
caption="Number of plots per Ecoregion") %>%
summarize(num.plot=n()) %>%
arrange(desc(num.plot)) %>%
slice(1:30),
caption="Number of plots in the 30 best represented Ecoregions") %>%
Extract elevation for each plot. Loops over tiles of 1 x 1°, projects to mercator, and extract elevation for plot coordinates, as well as 2.5, 50, and 97.5 quantiles for a buffer area having a radius equal to the location uncertainty of each plot (but only if location uncertainty < 50 km). DEM derive from package [elevatr](https://cran.r-project.org/web/packages/elevatr/vignettes/introduction_to_elevatr.html#get_raster_elevation_data), which uses the [Terrain Tiles on Amazon Web Services](https://registry.opendata.aws/terrain-tiles/). Resolutions of DEM rasters vary by region. I set a zoom factor z=10, which corresponds to ~ 75-150 m. Sources are: SRTM, data.gov.at in Austria, NRCAN in Canada, SRTM, NED/3DEP 1/3 arcsec, data.gov.uk in United Kingdom, INEGI in Mexico, ArcticDEM in latitudes above 60°, LINZ in New Zealand, Kartverket in Norway, as described [here](https://github.com/tilezen/joerd/blob/master/docs/data-sources.md).
This report documents how environmental variables were extracted when constructing sPlot 3.0. It is based on dataset sPlot_3.0.2, received on 24/07/2019 from Stephan Hennekens.