Convert EPSG Code to CRS String

This function converts an EPSG code into a corresponding coordinate reference system (CRS) string in PROJ.4 format. The EPSG code is a standard identifier used for geographic coordinate systems.

Usage

epsg(x)

Arguments

x

An integer or numeric value representing the EPSG code. For example, 4326 corresponds to WGS 84.

Value

A character string in PROJ.4 format that represents the CRS associated with the given EPSG code.

Details

The function attempts to convert an EPSG code into its corresponding PROJ.4 string using the sp package. If the conversion fails (e.g., due to an invalid or unsupported EPSG code), the function will stop and return an error message.

The EPSG code is a widely used identifier for coordinate reference systems. This function simplifies the process of obtaining the corresponding PROJ.4 string, which can then be used in various spatial analysis tasks.

References

European Petroleum Survey Group (EPSG). Geodetic Parameter Dataset. https://epsg.org/

Bivand, R. S., Pebesma, E., & Gómez-Rubio, V. (2013). Applied Spatial Data Analysis with R (2nd ed.). Springer. doi:10.1007/978-1-4614-7618-4

Examples

# Convert EPSG code 4326 to PROJ.4 string
epsg(4326)
#> [1] "+proj=longlat +datum=WGS84 +no_defs"

# Convert EPSG code 28992 (RD New / Amersfoort)
epsg(28992)
#> [1] "+proj=sterea +lat_0=52.1561605555556 +lon_0=5.38763888888889 +k=0.9999079 +x_0=155000 +y_0=463000 +ellps=bessel +units=m +no_defs"

# Handling an invalid EPSG code (this will return an error)
if (FALSE) { # \dontrun{
epsg(999999)
} # }