degree: decimal degree coordinate conversion

In brry/OSMscale: Add a Scale Bar to 'OpenStreetMap' Plots

decimal degree coordinate conversion

Description

Convert latitude-longitude coordinates between decimal representation and degree-minute-second notation

Usage

degree(
  lat,
  long,
  data,
  todms = !is.character(lat),
  digits = 1,
  drop = FALSE,
  quiet = FALSE
)

Arguments

lat, long	Latitude (North/South) and longitude (East/West) coordinates in decimal degrees
data	Optional: data.frame with the columns lat and long
todms	Logical specifying direction of conversion. If FALSE, converts to decimal degree notation, splitting coordinates at the symbols for degree, minute and second (\U00B0, ', "). DEFAULT: !is.character(lat)
digits	Number of digits the seconds are rounded to. DEFAULT: 1
drop	Drop to lowest dimension? DEFAULT: FALSE
quiet	Logical: suppress non-df warning in getColumn? DEFAULT: FALSE

Value

data.frame with x and y as character strings or numerical values, depending on conversion direction

Author(s)

Berry Boessenkool, [e-mail], Aug 2016

See Also

earthDist, projectPoints for geographical reprojection

Examples

# DECIMAL to DMS notation: --------------------------------------------------
degree(52.366360, 13.024181)
degree(c(52.366360, -32.599203), c(13.024181,-55.809601))
degree(52.366360, 13.024181, drop=TRUE) # vector
degree(47.001, -13.325731, digits=5)

# Use table with values instead of single vectors:
d <- read.table(header=TRUE, sep=",", text="
lat, long
 52.366360,  13.024181
-32.599203, -55.809601")
degree(lat, long, data=d)

# DMS to DECIMAL notation: --------------------------------------------------
# You can use the degree symbol and escaped quotation mark (\") as well.
degree("52'21'58.9'N", "13'1'27.1'E")
print(degree("52'21'58.9'N", "13'1'27.1'E"), digits=15)

d2 <- read.table(header=TRUE, stringsAsFactors=FALSE, text="
lat long
52'21'58.9'N 13'01'27.1'E
32'35'57.1'S 55'48'34.6'W") # columns cannot be comma-separated!
degree(lat, long, data=d2)

# Rounding error checks: ----------------------------------------------------
oo <- options(digits=15)
d
degree(lat, long, data=degree(lat, long, d))
degree(lat, long, data=degree(lat, long, d, digits=3))
options(oo)
stopifnot(all(degree(lat,long,data=degree(lat,long,d, digits=3))==d))

brry/OSMscale documentation built on Oct. 14, 2023, 6:27 a.m.