make_EPSG: Make a data frame of EPSG projection codes

Description

Make a data frame of the European Petroleum Survey Group (EPSG) geodetic parameter dataset as distributed with PROJ.4 software (prior to PROJ 6.0.0, March 2019, only the CSV file, from March 2019 with PROJ >= 6 from the SQLite database). Because finding the correct projection specification is not easy, lists still known as EPSG lists are maintained, and more generally retrieved from databases. The data collated here are as distributed with PROJ.4.

Usage

make_EPSG(file)

Arguments

file

file name of the file matching EPSG codes and PROJ.4 arguments, should usually be autodetected; not used for PROJ >= 6

Value

returns a data frame with columns:

code

integer column of EPSG code numbers

note

character column of notes as included in the file

prj4

character column of PROJ.4 arguments for the equivalent projection definitions

prj_method

extra character column from PROJ 6 showing the projection method

...

References

The correct link is: http://www.epsg.org/ but it fails for many users because it is HTTP, and is treated as insecure.

Examples

Run this code

# NOT RUN {
EPSG <- try(make_EPSG())
# from PROJ 6.0.0, EPSG data is no longer stored in a flat file
if (!inherits(EPSG, "try-error")) attr(EPSG, "metadata") 
# PROJ.4 5.0.0 and later include EPSG version
if (!inherits(EPSG, "try-error")) EPSG[grep("Oslo", EPSG$note), 1:2]
if (!inherits(EPSG, "try-error")) EPSG[1925:1927, 3]
if (!inherits(EPSG, "try-error")) EPSG[grep("Poland", EPSG$note), 1:2]
if (!inherits(EPSG, "try-error")) EPSG[grep("Amersfoort", EPSG$note), 1:2]
if (!inherits(EPSG, "try-error")) EPSG[grep("North Carolina", EPSG$note), 1:2]
if (!inherits(EPSG, "try-error")) EPSG[2202, 3]
# }