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Construct a BlueTopo native-resolution policy

Source: R/resolution.R
bluertopo_resolution.Rd

bluertopo_resolution() creates an explicit native source-tile selection policy. Smaller meter values are finer source resolution. This object never requests output resampling; use output_resolution in bluertopo() for an explicit output grid.

Usage

bluertopo_resolution(
  strategy,
  value = NULL,
  values = NULL,
  min_m = NULL,
  max_m = NULL,
  n = NULL,
  scope = "global",
  tie = "finer",
  prefer = "finest",
  strict = TRUE,
  min_coverage = 1
)

Arguments

strategy

A character scalar naming a strategy: "native", "finest", "coarsest", "best_available", "coarsest_available", "dominant", "exact", "nearest", "finer_or_equal", "coarser_or_equal", "between", "rank", "finest_n", "coarsest_n", "target", or "coverage". "highest" and "lowest" are aliases for "finest" and "coarsest".

value

NULL or one positive numeric native cell size in meters. Required by "nearest", "target", "finer_or_equal", and "coarser_or_equal".

values

NULL or a numeric vector of positive native cell sizes in meters. Required by "exact".

min_m, max_m

NULL or positive numeric inclusive bounds in meters. Both are required by "between".

n

NULL or a positive whole number used by "rank", "finest_n", and "coarsest_n".

scope

A character scalar. Only "global" is implemented; "local" is reserved and rejected.

tie

A character scalar, "finer" or "coarser", used when two native resolutions are equally close to a target.

prefer

A character scalar, "finest" or "coarsest", controlling ordering for coverage and rank strategies.

strict

A length-one logical. If TRUE, coverage fallback stays within hard resolution constraints.

min_coverage

A numeric value from 0 through 1 used by the "coverage" strategy.

Value

A bluertopo_resolution S3 object containing the normalized policy fields. Pass it to the resolution argument of bluertopo(), bluertopo_tiles(), or bluertopo_download().

Examples

bluertopo_resolution("nearest", value = 10, tie = "finer")
#> <bluertopo_resolution>
#>   strategy: nearest 
#>   value: 10 m
#>   scope: global 
#>   strict: TRUE 
bluertopo_resolution("between", min_m = 4, max_m = 16)
#> <bluertopo_resolution>
#>   strategy: between 
#>   bounds: 4 to 16 m
#>   scope: global 
#>   strict: TRUE