I'm extracting mean values from a raster with polygon shapefile. The CRS of both raster and vector are same, but then also extract function returns NA values.
library(rgdal)
library(raster)
options(stringsAsFactors = FALSE)
Shapefile <- readOGR("Fishnet_geolocated.shp",layer="Fishnet_geolocated")
plot(Shapefile)
CHM_Napi<-raster("Napi_CRS.tif")
crs(Shapefile)
crs(CHM_Napi)
Napi_extract <- raster::extract(CHM_Napi, # the raster that you wish to extract values from
Shapefile, # a point, or polygon spatial object
fun = mean, # extract the MEAN value from each plot
sp = TRUE) # create spatial object
class(Napi_extract)
summary(Napi_extract$Napi_CRS)
After running this code I get a result-
> Shapefile <- readOGR("Fishnet_geolocated.shp",layer="Fishnet_geolocated")
OGR data source with driver: ESRI Shapefile
Source: ""
with 63 features
It has 5 fields
Integer64 fields read as strings: id
> plot(Shapefile)
> CHM_Napi<-raster("Napi_CRS.tif")
> crs(Shapefile)
CRS arguments:
+proj=utm +zone=36 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84
+towgs84=0,0,0
> crs(CHM_Napi)
CRS arguments:
+proj=utm +zone=36 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84
+towgs84=0,0,0
> class(Napi_extract)
[1] "SpatialPolygonsDataFrame"
attr(,"package")
[1] "sp"
> summary(Napi_extract$Napi_CRS)
Min. 1st Qu. Median Mean 3rd Qu. Max. NA's
NA NA NA NaN NA NA 63
Is there something which I'm missing in the extract function, should I reproject the raster and shapefile. P.S. In QGIS both the vector and raster layer overlap, but not in R. Any useful tips are appreciated.
