Raster output from rasterized sf points does not align with points - r

Question

I am trying to rasterize some points and am getting a mismatch between the points and the rasters despite the crs being the same. If I convert the raster to polygons it lines up perfectly with the sf points data, but I can't figure out why the raster doesn't.
library(spData)
library(sf)
library(raster)
library(mapview)
## import some data
cycle_hire_osm = spData::cycle_hire_osm
## project to metres
cycle_hire_osm_projected = st_transform(cycle_hire_osm, crs = 27700)
## create raster template to rasterize to
raster_template <- raster(extent(cycle_hire_osm_projected), nrows = 10, ncols = 10, crs = 27700)
## rasterize the points
ch_raster1 = rasterize(cycle_hire_osm_projected, raster_template, field = 'capacity',
fun = sum, crs = 27700)
## convert raster to polygons
ch_poly <- rasterToPolygons(ch_raster1)
If these are plotted there are raster cells that have a value but have no points in.
## plot on a map
mapview(ch_poly)+cycle_hire_osm_projected+ch_raster1
Additional example based on reply to show the output as base, mapview and leaflet (note: I had to install the development versions of mapview and leaflet in order to plot SpatRasts)
library(spData)
library(sf)
library(terra)
library(dplyr)
# remove NAs so they are not considered
dat <- spData::cycle_hire_osm %>% filter(!is.na(capacity))
v <- vect(dat)
r <- rast(v, nrows=10, ncols=10)
chr <- rasterize(v, r, field="capacity", fun=sum, na.rm=TRUE)
## base plot
plot(chr)
points(v, cex=.5)
points(v[is.na(v$capacity)], cex=.5, col="red")
## mapview
library(mapview)
mapview(v)+chr
##leaflet
library(leaflet)
leaflet() |>
addProviderTiles(providers$CartoDB.Positron) |>
addCircles(data = v) |>
addRasterImage(chr)
All three plots are the same raster but the raster appears to have a different number of cells with values in each plot?
Adding example with project = FALSE as explain by #RobertHijmans
leaflet() |>
addProviderTiles(providers$CartoDB.Positron) |>
addCircles(data = v) |>
addRasterImage(chr, project = FALSE)

Answer 1

I do not see that issue with "raster" nor with its replacement, "terra"
when using base-plot
library(spData)
library(terra)
# using a SpatVector for easier plotting; results are the same
v <- vect(spData::cycle_hire_osm)
v <- project(v, "epsg:27700")
r <- rast(v, nrows=10, ncols=10)
chr <- rasterize(v, r, field="capacity", fun=sum, na.rm=TRUE)
plot(chr)
points(v, cex=.5)
points(v[is.na(v$capacity)], cex=.5, col="red")
But note that there are some cells with values of zero where all values of v$capacity are NA. That is because
sum(NA, na.rm=TRUE)
#[1] 0
To avoid that from happening you could do
vv <- v[!is.na(v$capacity)]
chr <- rasterize(vv, r, field="capacity", fun=sum, na.rm=TRUE)
The reason you see differences when using mapview/leaflet is that these use transform your data to the crs that they use. To avoid that use the
Pseudo-Mercator (EPSG:3857) crs, and, in leaflet, use project=FALSE when adding the raster data.
addRasterImage(chr, project=FALSE)