This is kriging script that i used tointerpolate and draw temperature and humidity heatmaps of Bosnia and Herzegovina. http://www.sule.io/heatmaps/

krigingScript.R

doAllYear <- function(weather){
  
  for (i in 1:12 ){
    
    month <- getDataForMonth(weather, i)
    krigeAndPlot(month) 
  }
  
  print("JOB DONE")
}

krigeAndPlot <- function(data){
  
  require(geoR)
  require(fields)
  
  data <- addExtremePoints(data)
  month = intToMonth(data[1, "month"])
  points <- cbind(data$longitude, data$latitude)
  temperature_model <- likfit(data = data$temperature, coords = points, 
                              fix.nugget = F, cov.model = "exponential" , ini = c(30, 5), nugget = 5)
  print(paste("[", month, "] Temperature model summary: "))
  print(summary(temperature_model))
  
  precipitation_model <- likfit(data = data$precipitation, coords = points, 
                                fix.nugget = F, cov.model = "exponential" , ini = c(30, 5), nugget = 5)
  print(paste("[", month, "] Precipitation model summary: "))
  print(summary(precipitation_model))
  
  longitude <- seq(min(points[,1]), max(points[,1]), length = 1000)
  latitude <- seq(min(points[,2]), max(points[,2]), length = 1000)
  
  spatial <- expand.grid(longitude, latitude)
  
  print(paste("[", month, "] Temperature kriging started..."))
  temperature_prediction <- krige.conv(data=data$temperature,coords=points,locations=spatial,
                           krige=krige.control(cov.model="exponential",
                                               cov.pars=c(temperature_model$sigmasq , temperature_model$phi), 
                                               nugget = temperature_model$nugget))
  print(paste("[", month, "] Temperature kriging ended."))
  
  print(paste("[", month, "] Precipitation kriging started..."))
  precipitation_prediction <- krige.conv(data=data$precipitation,coords=points,locations=spatial,
                           krige=krige.control(cov.model="exponential",
                                               cov.pars=c(precipitation_model$sigmasq , precipitation_model$phi), 
                                               nugget = precipitation_model$nugget))
  print(paste("[", month, "] Precipitation kriging ended."))
  
  print(paste("[", month, "] Cutting needless points from prediction..."))
  temperature_prediction <- cutShape(spatial, temperature_prediction)
  precipitation_prediction <- cutShape(spatial, precipitation_prediction)
  
  print(paste("[", month, "] Plotting..."))
  
  
  image.plot(longitude,latitude,matrix(temperature_prediction$predict,1000,1000), 
             legend.lab=paste("Prosjecna temperatura za mjesec ", month, " 2014 (Celsius)"), zlim = (range(-7, 25)),
              bg = "transparent",
             legend.args=list( text="°C",col="magenta", cex=1.5, side=4, line=2)) 
  image.plot(longitude,latitude,matrix(precipitation_prediction$predict,1000,1000), 
             legend.lab=paste("Prosjecne padavine za mjesec ", month, " 2014. (mm/m2)"), zlim = (range(15, 290)), 
              border = "grey", lwd=2, col = two.colors(n=256, start="red", end="blue", middle = "white"), 
             bg = "transparent", legend.args=list( text="mm/m2",col="magenta", cex=1, side=6, line=1))
  
  save(temperature_model, precipitation_model,  file = paste("/Users/sulejmansararajlija/R_data/" , month , "_models.RData"))
  save(temperature_prediction, precipitation_prediction,  
       file = paste("/Users/sulejmansararajlija/R_data/" , month , "_predictions.RData"))
  
  spatial$temperature <- temperature_prediction$predict
  spatial$precipitation <- precipitation_prediction$predict
  
  names(spatial)[names(spatial)=="Var1"] <- "longitude"
  names(spatial)[names(spatial)=="Var2"] <- "latitude"
  
  write.table(spatial, paste("/Users/sulejmansararajlija/R_data/" , month , ".csv"), sep="\t")
}

cutShape <- function(set, prediction){
  
  require(SDMTools)
  require(raster)
  
  polygon <- getData('GADM', country="Bosnia and Herzegovina", level=0)
  intersection <- pnt.in.poly(set, polygon@polygons[[1]]@Polygons[[1]]@coords)
  
  for(s in 1:nrow(set)){
    if(intersection[s,"pip"] == FALSE)
      prediction$predict[s] <- NA
  }
  
  return(prediction)
}

getDataForMonth <- function(weather, month){
  
  monthly_weather <- weather[0,]
  
  for (i in 1:nrow(weather)) {
    
    if(weather[i, "month"] == month){
      monthly_weather <- rbind(monthly_weather, weather[i,])
    }
  } 
  
  return(monthly_weather)
}

addExtremePoints <- function(month){
  
  month <- rbind( month, data.frame("latitude" = 45.27 , "longitude" = 15.73, "precipitation" = month[100, 
                                        "precipitation"], "altitude" = month[100, "altitude"], "station_id" = month[100, 
                                       "station_id"],"month" = month[100, "month"],"temperature" = month[100, "temperature"], 
                                     "row.names" = 0))
  
  month <- rbind( month, data.frame("latitude" = 44.2 , "longitude" = 19.61, "precipitation" = month[12,"precipitation"], 
                                     "altitude" = month[12, "altitude"], "station_id"  = month[12, "station_id"],
                                    "month" = month[12, "month"],"temperature" = month[12, "temperature"], 
                                     "row.names" = 0))
  
  month <- rbind( month, data.frame("latitude" = 42.57, "longitude" = 18.4, "precipitation" = month[97,"precipitation"], 
                                     "altitude" = month[97, "altitude"], "station_id" = month[97, "station_id"],
                                     "month" = month[97, "month"],"temperature" = month[97, "temperature"], 
                                     "row.names" = 0))
  
  return(month)

}

intToMonth <- function(number){
  
  options(warn=-1)
  
  if (number == 1)
    month = "januar"
  else if (number == 2)
    month = "februar"
  else if (number == 3)
    month = "mart"
  else if (number == 4)
    month = "april"
  else if (number == 5)
    month = "maj"
  else if (number == 6)
    month = "jun"
  else if (number == 7)
    month = "jul"
  else if (number == 8)
    month = "august"
  else if (number == 9)
    month = "septembar"
  else if (number == 10)
    month = "oktobar"
  else if (number == 11)
    month = "novembar"
  else if (number == 12)
    month = "decembar"
  else
    print("Wrong number")
    
  return(month)  
}