Unable to project simple features or change projection - r

Question

I am trying to convert a csv to an sf spatial data file, however I'm getting errors that I cant' figure out.
Example:
library(tidyverse)
library(sf)
#> Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1
point_df <- tibble::tribble(
~city_name, ~longitude, ~latitude,
"Akron", -81.5190053, 41.0814447,
"Albany", -73.7562317, 42.6525793,
"Schenectady", -73.9395687, 42.8142432,
"Albuquerque", -106.650422, 35.0843859,
"Allentown", -75.4714098, 40.6022939,
"Bethlehem", -75.3704579, 40.6259316,
"Atlanta", -84.3879824, 33.7489954,
"Augusta", -82.0105148, 33.4734978,
"Austin", -97.7430608, 30.267153,
"Bakersfield", -119.0187125, 35.3732921
)
point_sf <- st_as_sf(point_df, coords = c("longitude", "latitude"))
point_sf <- st_set_crs(point_sf, 4326)
st_transform(point_sf, 102003)
#> Warning in CPL_crs_from_input(x): GDAL Error 1: PROJ: proj_create_from_database:
#> crs not found
#> Error in CPL_transform(x, crs, aoi, pipeline, reverse): crs not found: is it missing?
Any help would be greatly appreciated.
EDIT
I found a kludgy solution which I adapted from this github page, but I am stil looking for a more systematic solution if possible. https://github.com/r-spatial/sf/issues/1419
The solution here is to convert the sf object into sp then change back to sf.
reProject <- function (sf, proj_in = "+init=epsg:4326",
proj_out = "+proj=aea +lat_1=20 +lat_2=60 +lat_0=40 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs") {
require(sp)
data_sp <- as(sf, "Spatial")
proj4string(data_sp) <- CRS(proj_in)
sf_out <- st_as_sf(spTransform(data_sp, CRS(proj_out)))
}
dat_out <- reProject(point_sf)

Answer 1

It appears something was expected to happen with the following line of code. But that something is not happening.
point_sf <- st_as_sf(point_df, coords = c("longitude", "latitude"))
While this line of code creates the simple feature geometric point objects, this code does not create the simple feature geometry column (sfc) object. And since there is no sfc object, the next line of code does not work.
point_sf <- st_set_crs(point_sf, 4326)
In this other line of code, the function, st_set_crs(), retrieves a coordinate reference system from sf or sfc objects. But neither the sf or the sfc objects currently exist.
Therefore, the sfc object must be first created before using the function: st_set_crs().
It really helps to follow the following steps whenever doing these types of simple feature projects.
x.sfg <- st_multipoint(c(lon,lat), dim = "XY") # create sf geometry from lon/lat
x.sfc <- st_sfc(x.sfg, crs = 4326) # create sfc from geometry
x.sf <- st_sf(df, x.sfc) # create sf object from sfc
First convert the log and lat to vectors, then create the matrix, and then create the simple feature objects in the correct progression.
lon <- c(-81.5190053, -73.7562317, -73.9395687, -106.650422, -75.4714098, -75.3704579, -84.3879824, -82.0105148, -97.7430608, -119.0187125)
lat <- c(41.0814447, 42.6525793, 42.8142432, 35.0843859, 40.6022939, 40.6259316, 33.7489954, 33.4734978, 30.267153, 35.3732921)
m <- matrix(data = c(lon, lat), nrow = 10, ncol = 2, byrow = FALSE)
m.sfg <- st_multipoint(m, dim = "XY")
m.sfc <- st_sfc(m.sfg, crs = 4326)
m.sf <- st_sf(df, m.sfc)
head(m.sf, 3)
Then create a base plot of the continental US, and then plot the simple feature object onto the base map.
plot(US_48, axes = TRUE)
plot(m.sf, add= TRUE, pch = 19, col = "red")
The link shown above with the question does not seem to have anything related to this question. The answer shown here does not convert the sf object into sp then change back to sf.
The plot is shown at link: