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Look Up Package Representative Vs30 Values

SIDtoVs30.Rd

Converts package site identifiers to representative values of Vs30, the time-averaged shear-wave velocity through the upper 30 m. Use this lookup when an API requires one package representative value for each identifier.

Usage

SIDtoVs30(SID = NULL)

Arguments

SID

A character vector or factor containing one or more of "A", "AB", "B", "BC", "C", "CD", "D", "DE", or "E". Matching is case-insensitive. Whitespace is not removed. NULL and zero-length inputs are accepted.

Value

For a non-empty input, a numeric vector with the same length and order as SID, containing representative Vs30 values in meters per second (m/s). A named input retains its names. An unnamed character input gains names equal to its original identifiers, including their original case; an unnamed factor produces an unnamed result. NULL and zero-length inputs return an empty list rather than numeric(0).

Details

The package lookup is:

  • "A" and "AB": 1500 m/s;

  • "B": 1200 m/s;

  • "BC": 760 m/s;

  • "C": 540 m/s;

  • "CD": 370 m/s;

  • "D": 255 m/s;

  • "DE": 180 m/s; and

  • "E": 150 m/s.

Validation is all-or-nothing: if any element is missing or is not one of the nine identifiers after case conversion, the call stops with an error and returns no partial result. In particular, "F" is unsupported. Apart from NULL, supported inputs are character vectors and factors; other input classes are outside the public contract.

Package policy and reverse classification

These are package-defined representative lookup values, not interval midpoints, site-class boundaries, or a standards classification. Vs30toSID() applies a separate numeric classification and is not the mathematical inverse of this lookup. For example, "A" and "AB" both map to 1500 m/s, so the original identifier cannot always be recovered from the representative value.

Side effects

Successful calls are deterministic and do not mutate SID, consume the random-number generator, issue warnings or messages, or access files or the network.

See also

Vs30toSID()

Examples

SID <- c("bc", "C", "DE")
Vs30 <- SIDtoVs30(SID)
Vs30
#>  bc   C  DE 
#> 760 540 180 
unname(Vs30)
#> [1] 760 540 180
# The three representative values are 760, 540, and 180 m/s, in input order.