Wraps the ISRO Bhuvan NTL REST API to return mean radiance per Indian state across years.

Usage

bhuvan_stats(years = NULL, state = NULL)

Arguments

years: Integer vector of years to return. NULL (default) returns all available years (currently 2012-2024).
state: Character. State name as returned by the API (e.g., "BIHAR"). NULL (default) returns all states.

Value

A tidy data frame with columns state (character), year (integer), and mean_radiance (numeric). State names are normalised to title case (e.g., "Tamil Nadu" not "TAMILNADU").

Details

For district-level or custom-geometry statistics, use bhuvan_raster() together with extract_panel().

Collection break

Bhuvan NTL data from 2024 onwards is derived from VNP46A4 Collection 2.0, while 2012-2023 uses the legacy Collection 1.0. The two collections use different calibration and atmospheric correction algorithms, so radiance estimates are not directly comparable across this boundary. Requests spanning both collections trigger a warning.

Examples

if (FALSE) { # \dontrun{
# All states, all years
df <- bhuvan_stats()

# Bihar only
df <- bhuvan_stats(state = "BIHAR")

# Multiple years
df <- bhuvan_stats(years = 2015:2023)
} # }