nasa (version 1.0.0)

get_earthdata: Search NASA Earthdata Collections Metadata

Description

Queries NASA's Common Metadata Repository (CMR) to search Earth science datasets related to a specified keyword. Optionally filters results by a temporal range.

Usage

get_earthdata(keyword, n_results, start_date = NULL, end_date = NULL)

Value

A data frame containing metadata about the matching datasets, with only cleaned column names (columns with '.' or '$' removed).

Arguments

keyword

Character. A search term or phrase used to find relevant datasets in titles, descriptions, keywords, and provider names.

n_results

Integer. The number of dataset entries to retrieve. If more than 2000, multiple pages will be requested automatically.

start_date

Character or NULL. Optional start date filter in "YYYY-MM-DD" format. If provided, must be used with end_date.

end_date

Character or NULL. Optional end date filter in "YYYY-MM-DD" format. If provided, must be used with start_date.

Details

CMR is the Earthdata search engine, the backend database that stores metadata about:

- Satellite datasets - Earth science data (climate, ocean, atmosphere, land) - Observational granules (single files like images, temperature readings, etc.) - Services (subsetting, reformatting, and other data services)

The search finds matches based on the keyword provided. The keyword can appear in:

- Dataset titles - Dataset descriptions - Dataset keywords (tags) - Some provider names

The function accesses the CMR API endpoint: https://cmr.earthdata.nasa.gov/ search/collections.json (Note: This is an API endpoint and may return an error when opened in a browser.) It harmonizes columns across API pages and returns up to the number of requested results. If no results are found, an empty data frame is returned.

Examples

if (FALSE) {
# Search for 1 dataset related to sea surface temperature
results <- get_earthdata(keyword = "sea surface temperature", n_results = 1)

# Search with a temporal constraint
results_time <- get_earthdata(
  keyword = "sea surface temperature",
  n_results = 1,
  start_date = "2020-01-01",
  end_date = "2020-01-02"
)
}