Introduction to the parzer package

parzer parses messy coordinates

You may get data from a published study or a colleague, and the coordinates may be in some messy character format that you’d like to clean up to have all decimal degree numeric data.

parzer API:

parse_hemisphere
parse_lat
parse_lon
parse_lon_lat
parse_parts_lat
parse_parts_lon
pz_d
pz_degree
pz_m
pz_minute
pz_s
pz_second

Install

Stable version

install.packages("parzer")

Development version

remotes::install_github("ropensci/parzer")

parse

library("parzer")

latitudes

parse_lat("45N54.2356")
#> [1] 45.90393
parse_lat("-45.98739874")
#> [1] -45.9874
parse_lat("40.123°")
#> [1] 40.123
parse_lat("40.123N")
#> [1] 40.123
parse_lat("N45 04.25764")
#> [1] 45.07096

# bad values -> NaN
parse_lat("191.89")
#> Warning in pz_parse_lat(lat): not within -90/90 range, got: 191.89
#>   check that you did not invert lon and lat
#> [1] NaN

# many inputs
x <- c("40.123°", "40.123N74.123W", "191.89", 12, "N45 04.25764")
parse_lat(x)
#> Warning in pz_parse_lat(lat): invalid characters, got: 40.123n74.123w

#> Warning in pz_parse_lat(lat): not within -90/90 range, got: 191.89
#>   check that you did not invert lon and lat
#> [1] 40.12300      NaN      NaN 12.00000 45.07096

# parse_lat("N455698735", "HDDMMmmmmm") # custom formats not ready yet

longitudes

parse_lon("45W54.2356")
#> [1] -45.90393
parse_lon("-45.98739874")
#> [1] -45.9874
parse_lon("40.123°")
#> [1] 40.123
parse_lon("74.123W")
#> [1] -74.123
parse_lon("W45 04.25764")
#> [1] -45.07096

# bad values
parse_lon("361")
#> Warning in pz_parse_lon(lon): not within -180/360 range, got: 361
#> [1] NaN

# many inputs
x <- c("45W54.2356", "181", 45, 45.234234, "-45.98739874")
parse_lon(x)
#> [1] -45.90393 181.00000  45.00000  45.23423 -45.98740

# parse_lon("N455698735", "HDDMMmmmmm") # custom formats not ready yet

both lon and lat together

lons <- c("45W54.2356", "181", 45, 45.234234, "-45.98739874")
lats <- c("40.123°", "40.123N", "191.89", 12, "N45 04.25764")
parse_lon_lat(lons, lats)
#>         lon      lat
#> 1 -45.90393 40.12300
#> 2 181.00000 40.12300
#> 3  45.00000      NaN
#> 4  45.23423 12.00000
#> 5 -45.98740 45.07096

parse into degree, min, sec parts

parse_parts_lat("45N54.2356")
#>   deg min      sec
#> 1  45  54 14.13674
parse_parts_lon("-74.6411133")
#>   deg min      sec
#> 1 -74  38 28.00784
# many inputs
x <- c("40.123°", "40.123N74.123W", "191.89", 12, "N45 04.25764")
parse_parts_lon(x)
#>   deg min      sec
#> 1  40   7 22.80395
#> 2  NA  NA      NaN
#> 3 191  53 23.99783
#> 4  12   0  0.00000
#> 5  NA  NA      NaN

get hemisphere from lat/lon coords

parse_hemisphere("74.123E", "45N54.2356")
#> [1] "NE"
parse_hemisphere("-120", "40.4183318")
#> [1] "NW"
parse_hemisphere("-120", "-40.4183318")
#> [1] "SW"
parse_hemisphere("120", "-40.4183318")
#> [1] "SE"

get degree, minutes, or seconds separately

coords <- c(45.23323, "40:25:6N", "40° 25´ 5.994\" N")
pz_degree(lat = coords)
#> [1] 45 40 40
pz_minute(lat = coords)
#> [1] 13 25 25
pz_second(lat = coords)
#> [1] 59.630119  6.005895  5.992162

coords <- c(15.23323, "40:25:6E", "192° 25´ 5.994\" E")
pz_degree(lon = coords)
#> [1]  15  40 192
pz_minute(lon = coords)
#> [1] 13 25 25
pz_second(lon = coords)
#> [1] 59.626686  6.005895  6.005895

add or subtract degrees, minutes, or seconds

pz_d(31)
#> 31
pz_d(31) + pz_m(44)
#> 31.73333
pz_d(31) - pz_m(44)
#> 30.26667
pz_d(31) + pz_m(44) + pz_s(59)
#> 31.74972
pz_d(-121) + pz_m(1) + pz_s(33)
#> -120.9742

Scott Chamberlain

2020-03-26