I have POINT_X, POINT_Y, and a z-point column in a .csv file that I'm trying to reproject in R. Originally, it was projected in the EPSG:26777 reference system, but I'm trying to project it back to WGS 84. However, when I import the .csv file into R and try the conversion, it does not change the point values in my "geometry" column. How can I change them to latitude and longitude coordinates?
Here is the data, exported in the original projection:
data <- data.frame(point_x = c(2387371.258,
2387411.214,
2387451.258,
2387529.427,
2387411.258,
2387191.258,
2387491.258,
2387331.258,
2387116.239,
2387291.258,
2387371.258,
2387431.258,
2387331.258,
2387271.258,
2387511.258,
2387331.258,
2387211.258,
2387351.258,
2387112.752,
2387311.22,
2387411.258,
2387191.258,
2387271.258,
2387491.258,
2387131.258,
2387231.258,
2387291.258,
2387371.052,
2387491.258,
2387171.258,
2387131.258,
2387371.258,
2387113.437,
2387211.258,
2387531.258,
2387331.258,
2387371.258,
2387311.258,
2387291.258,
2387511.258,
2387211.258,
2387491.258,
2387391.258,
2387530.847,
2387542.074,
2387491.258,
2387511.258,
2387271.258,
2387161.36,
2387112.772,
2387451.258,
2387431.258,
2387511.258,
2387127.551,
2387531.258,
2387251.258,
2387151.258,
2387231.258,
2387231.258,
2387191.258,
2387511.258,
2387171.258,
2387231.258,
2387431.258,
2387531.258,
2387231.258,
2387211.258,
2387112.281,
2387191.258,
2387391.258,
2387182.737,
2387351.258,
2387271.258,
2387371.258,
2387451.197,
2387171.258,
2387451.258,
2387431.258,
2387114.101,
2387491.219,
2387151.258,
2387451.258,
2387171.258,
2387528.481,
2387251.258,
2387251.258,
2387451.258,
2387112.193,
2387391.258,
2387151.258,
2387211.258,
2387171.258,
2387351.258,
2387131.258,
2387511.258,
2387411.258,
2387351.258,
2387411.258,
2387231.258,
2387211.224,
2387311.258,
2387191.258,
2387351.258,
2387351.258,
2387351.258,
2387171.258,
2387491.258,
2387371.258,
2387171.225,
2387251.258,
2387118.495,
2387231.258,
2387471.258,
2387171.258,
2387131.258,
2387191.258,
2387371.258,
2387151.258,
2387131.258,
2387411.258,
2387112.44,
2387191.258,
2387524.317,
2387391.258,
2387371.258,
2387251.258,
2387451.258,
2387371.258,
2387191.258,
2387231.258,
2387211.258,
2387331.258,
2387391.258,
2387311.258,
2387191.258,
2387431.258,
2387271.258,
2387271.258,
2387323.356,
2387231.258,
2387351.258,
2387191.258,
2387211.258,
2387231.258,
2387431.258,
2387191.258,
2387351.258,
2387491.258,
2387431.258),
point_y = c(289191.3991,
289054.1412,
289391.3991,
289351.3027,
289091.399,
289071.399,
289251.399,
289291.3993,
289271.587,
289311.3992,
289311.3992,
289151.3992,
289151.3992,
289131.3989,
289411.399,
289391.3991,
289071.399,
289331.3992,
289611.4751,
289053.1858,
289211.3991,
289511.3991,
289511.3991,
289171.3992,
289131.3989,
289371.3991,
289131.3989,
289529.3496,
289451.3993,
289271.399,
289211.3991,
289371.3991,
289391.4699,
289231.399,
289251.399,
289411.399,
289331.3992,
289411.399,
289531.3991,
289371.3991,
289331.3992,
289431.399,
289251.399,
289291.3169,
289055.4637,
289131.3989,
289071.399,
289231.399,
289601.478,
289431.4643,
289291.3993,
289271.399,
289131.3989,
289626.1925,
289131.3989,
289291.3993,
289231.399,
289251.399,
289351.3991,
289351.3991,
289151.3992,
289431.399,
289111.399,
289091.399,
289111.399,
289491.3992,
289311.3992,
289571.3209,
289191.3991,
289071.399,
289582.6287,
289411.399,
289331.3992,
289471.3992,
289054.5359,
289191.3991,
289151.3992,
289231.399,
289351.4766,
289511.3581,
289071.399,
289171.3992,
289331.3992,
289391.2898,
289131.3989,
289411.399,
289311.3992,
289628.765,
289471.3992,
289411.399,
289431.399,
289251.399,
289471.3992,
289471.3992,
289451.3993,
289391.3991,
289151.3992,
289111.399,
289271.399,
289052.2304,
289111.399,
289231.399,
289311.3992,
289191.3991,
289371.3991,
289571.399,
289211.3991,
289511.3991,
289051.8482,
289171.3992,
289191.7413,
289451.3993,
289251.399,
289351.3991,
289231.399,
289331.3992,
289071.399,
289511.3991,
289591.399,
289451.3993,
289451.4619,
289491.3992,
289487.6817,
289091.399,
289111.399,
289431.399,
289231.399,
289211.3991,
289091.399,
289291.3993,
289171.3992,
289371.3991,
289411.399,
289391.3991,
289211.3991,
289491.3992,
289251.399,
289111.399,
289541.5201,
289311.3992,
289211.3991,
289291.3993,
289091.399,
289231.399,
289431.399,
289111.399,
289251.399,
289491.3992,
289071.399),
point_z = c(0,
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0))
Here is what I am trying to do:
#Open packages
library(pacman)
p_load(raster,
sf,
dplyr,
ggplot2,
scales,
magrittr,
gstat,
gridExtra,
raster,
sp,
automap,
mapview,
leaflet,
rgdal)
#Read in data, provided above
data <- read.csv('data.csv')
#Change to a spatial object and reproject to WGS84
data <- st_as_sf(data, coords = c('point_x', 'point_y'), crs = crs(' proj=longlat ellps=WGS84 datum=WGS84 no_defs'))
The result of the crs(data) command is:
Coordinate Reference System:
Deprecated Proj.4 representation: proj=longlat datum=WGS84 no_defs
WKT2 2019 representation:
GEOGCRS["unknown",
DATUM["World Geodetic System 1984",
ELLIPSOID["WGS 84",6378137,298.257223563,
LENGTHUNIT["metre",1]],
ID["EPSG",6326]],
PRIMEM["Greenwich",0,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8901]],
CS[ellipsoidal,2],
AXIS["longitude",east,
ORDER[1],
ANGLEUNIT["degree",0.0174532925199433,
ID["EPSG",9122]]],
AXIS["latitude",north,
ORDER[2],
ANGLEUNIT["degree",0.0174532925199433,
ID["EPSG",9122]]]]
The results above indicate that it has been reprojected successfully. However, running the glimpse(data) command shows that the coordinates are still in the original projection system:
Rows: 300
Columns: 2
$ point_z <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0~
$ geometry <POINT [°]> POINT (2387371 289191.4), POINT (2387411 289054.1), ~
How can I change these points to latitude and longitude points?
CodePudding user response：
To transform the data to lat/lon, first you need to load it with the original crs value.
data <- st_as_sf(data, coords = c('point_x', 'point_y'),
crs = 26777)
You'll get an sf object of the original data, with original coordinates, but now st_transform will know how to transform it to other coordinate systems:
data_latlong <- st_transform(data, crs = 4326)
Should give you coordinates in latitude/longitude values.