gsw_time_series_resource function

Helper function to download Global Surface Water (GSW) yearly time series data

This function constructs the necessary data URLs for a given data set, version and polygon and downloads them for further processing with the mapme.biodiversity package.

Source

Raw Data: https://jeodpp.jrc.ec.europa.eu/ftp/jrc-opendata/GSWE/YearlyClassification/LATEST/tiles/

get_gsw_time_series(years, version = "LATEST")

Arguments

• years: Numeric vector of years to process between 1984 and 2021. Default: 1984:2021.
• version: Version of the data set to process. Available options are (VER1-0, VER2-0, VER3-0, VER4-0, VER5-0 and LATEST) Default: LATEST. Choosing LATEST will result in the latest available version.

Returns

A function that returns a character vector of file paths.

Details

The available surface water classes for a given pixel are the following:

• No Observation: It was not possible to determine whether a pixel was water (this may be the case for frozen areas or during the polar night in extreme latitudes).
• Permanent Water: Water was detected in twelve months per year or in a combination of permanent and no observation.
• Seasonal Water: Water and no water was detected.
• No Water: No Water was detected.

References

• Global Surface Water Explorer: https://global-surface-water.appspot.com/
• Data Users Guide: https://storage.cloud.google.com/global-surface-water/downloads_ancillary/DataUsersGuidev2021.pdf
• Research Article: https://www.nature.com/articles/nature20584