> library(gstat) > library(readxl) > library(sp) > library(rgdal) #2013(FATALITIES) data <- read.csv("C:/Users/sbs/Desktop/Study/RA/Accident analysis/New folder/Iowa total crashes 2013_cleaned.csv", header = TRUE, sep =",") plot(data) attach(data) > class(data)  "data.frame" > coordinates(data) <- ~XCOORD+YCOORD > class(data)  "SpatialPointsDataFrame" attr(,"package")  "sp" > variogram1<- variogram(FATALITIES~1, data) > plot(variogram1) > fit.variogram1<- fit.variogram(variogram1, vgm(0.002, "Exp")) > plot(variogram1, fit.variogram1, cutoff = 300000, pch =20, col ="red") > fit.variogram1 model psill range 1 Exp 0.007896732 13527.15
Until this point everything looks good. My "data" is in CVS format, units meters. Fitted variogram model looks good.
I have made "X" my prediction surface or grid using ArcGIS having 500*500 meter as cell size of fishnet. It is a shapefile.
> x<- readOGR("H:/p/Road_Network_Info/road_fish_lable.shp") OGR data source with driver: ESRI Shapefile Source: "H:\p\Road_Network_Info\road_fish_lable.shp", layer: "road_fish_lable" with 5006 features It has 1 fields Integer64 fields read as strings: Id > plot(x) > class(x)  "SpatialPointsDataFrame" attr(,"package")  "sp"
Everything good until now. When I start performing kriging, this error shows up. But the plots of my "data" and Grid (X) overlap each other perfectly.
> krige(FATALITIES~1, data, x, fit.variogram1)  NA  "+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0" Error in predict.gstat(g, newdata = newdata, block = block, nsim = nsim, : var1 : data item in gstat object and newdata have different coordinate reference systems
I am performing analysis on fatalities in state of Iowa, USA. Here, both X and data are in meters with same coordinates. i have checked it twice. I am using NAD 1987 Coordinates in ArcGIS to make the required shapefile.