r - Wrong projection high quality shapefile for the coastline of Helsinki region (Finland)

I did some spatial interpolations in R and I need a support for those.

Looking for shapefiles online the best I could find was and it looks really horrible, the same area in ggplot looks like . I spent a lot of time on this, to no avail, I found shapefiles with any kind of informations, but nothing that has a good definition of the shore.

EDIT my code

rm(list=ls())
setwd("C:/Users/irene/Desktop/FIN_adm")

graphics.off()
Finland <- readOGR(".","FIN_adm0")
#OGR data source with driver: ESRI Shapefile 
#Source: ".", layer: "FIN_adm0"
#with 1 features and 70 fields
#Feature type: wkbMultiPolygon with 2 dimensions

#prj file says GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]

setwd("C:/tesi/Rtoshiba/dati/3 downtown")

data44 <- read.table("ch44.txt", header=T)
head(data44)
locations<-unique(cbind(data44[,1], data44[,2]))
#plot(locations)

media.stat44=vector(length=109)
media.rssi44=vector(length=109)

for (i in 1:109){
  temp<-data44[data44[,1]==locations[i,1] & data44[,2]==locations[i,2],]#location i

  media.stat44[i]<-mean(temp$stat)
  media.rssi44[i]<-mean(temp$rssi)
}

temp44<-cbind(locations, media.stat44)
xy <- temp44[,1:2]
df44 <- as.data.frame(temp44[,-1:-2])
SPDF44 <- SpatialPointsDataFrame(coords=xy, data=df44)



bbox = c(min(data44$lon), min(data44$lat),
         max(data44$lon), max(data44$lat))

predgrid <- expand.grid(lon=seq(from=bbox[1], to=bbox[3], length.out=400), 
                        lat=seq(from=bbox[2], to=bbox[4], length.out=400))

aa<-as.data.frame(rep(NA,160000))  
dimnames(aa)[[2]]<-"stat"
loc<-SpatialPointsDataFrame(coords=predgrid, data=aa)


ciccia44<-as.data.frame(df44)
dimnames(ciccia44)[[2]]<-"stat"
SPDFgri44<-SpatialPointsDataFrame(coords=locations, data=ciccia44)

stima44 <- idw(stat~1, SPDFgri44, loc, idp = 1.0, debug.level = 1)

library(raster)
rast44 <- raster(stima44)

f44<-as.data.frame(stima44)

# create spatial points data frame
spg <- f44
coordinates(spg) <- ~ x + y
# coerce to SpatialPixelsDataFrame
gridded(spg) <- TRUE
# coerce to raster
rasterDF <- raster(spg)
rasterDF
x11()
plot(rasterDF)


# setwd("C:/tesi/GIS_data/FIN_adm")
# #setwd("C:/Users/irene/Desktop/fi")
# 
# Finland <- readShapePoly("FIN_adm1.shp")
# Finland
# #str(Finland)
# unique(Finland@data$VARNAME_1)
# Finland <- Finland[Finland$VARNAME_1 == "Etelä-Suomen lääni|Södra Finlands län",]
vv<-fortify(Finland)


#prova subset sia giusto
#x11()
#plot(vv[,1], vv[,2])

projection(Finland) <- CRS("+proj=longlat +ellps=WGS84 +no_defs")

elevation.sub <- crop(rasterDF, extent(Finland))

elevation.sub <- mask(elevation.sub, Finland)


x11()
plot(elevation.sub)
plot(Finland, add = TRUE)

I downloaded (between others) the shapefile suggested in the answer, selected the tile I am interested in getting Code I used:

Finland2 <- readOGR(".","helsinki")


class       : SpatialPolygonsDataFrame 

features    : 1331 
extent      : 2704914, 2905588, 8392151, 8516090  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
variables   : 3
names       : error, tile_x, tile_y 
min values  :     0,    227,    283 
max values  :     0,    228,    284 
unique(Finland2@data$tile_x)
unique(Finland2@data$tile_y)

I select the tile I am interested into

Finland3 <- Finland2 [Finland2$tile_x == 227 &  Finland2$tile_y == 284, ]

And project it

Finland3<-spTransform(Finland3, CRS("+proj=longlat +ellps=WGS84 +no_defs+ellps=WGS84 +towgs84=0,0,0 "))

x11()
plot(Finland3)

Is the change of projection wrong? Because when I write Finland3 I get:

class       : SpatialPolygonsDataFrame 
features    : 742 
extent      : 24.29866, 25.20134, 60.23717, 60.68294  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=longlat +ellps=WGS84 +towgs84=0,0,0 
variables   : 3
names       : error, tile_x, tile_y 
min values  :     0,    227,    284 
max values  :     0,    227,    284 

This map shows the tile I want, but the geocoding is wrong at least north-south.

QUESTION:is the projection wrong?????

EDIT AFTER NEW SHP I still get wrong coordinates, this has extent (24.29866, 25.20134, 60.23717, 60.68294) (xmin, xmax, ymin, ymax) and if I check these on google maps they are not overlapping, but I need them to overlap my raster when I import I just do:

aa<-readOGR(".", "helsinki_wgs84")
unique(aa@data$tile_x)
unique(aa@data$tile_y)
aa3 <- aa [aa$tile_x == 227 &  aa$tile_y == 284, ]
Finland3<-spTransform(aa3, CRS("+proj=longlat +ellps=WGS84 +no_defs+ellps=WGS84 +towgs84=0,0,0 "))

x11()
plot(Finland3)

Answer

At the end I used the shapefile from the National Land survey of Finland even though not perfect, they seemed to be of a higher quality