Sea_level.Rmd

---
title: "Sea level data processing"
author: "UN"
date: "July 25, 2017"
output: html_document
editor_options: 
  chunk_output_type: console
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r Import raw sea level data}
sea_level_raw <- read.csv('Sea_level_rawdata.csv')
SL_2000 <- sea_level[sea_level$year==2000,]
```


```{r import libraries}
library(raster)
library(rasterVis)
library(maptools)
library(rgdal)
library(dplyr)
library(reshape2)
library (rgdal)
library(sp)
library(tidyr)
library(gstat)
```


```{r Interpolation}
#Create a function that extract sea level data to each of counties
#Import points
sea_level_extract <- function(sea_level){

  #remove NA from data
  sea_level <- sea_level %>% drop_na()

  #Create spatial points data frame
sea_level_sp <- sea_level
coordinates(sea_level_sp) <- ~long + lat
#Create raster grid

#Create spatial extent, x,y min, max
x_range <- as.numeric(c(-99,-80))
y_range <- as.numeric(c(24,32))

#Create values for grid
grd <- expand.grid(x=seq(from=x_range[1],to = x_range[2], by=.1), y=seq(from=y_range[1],to = y_range[2], by=.1))

#Convert grid to matrix
coordinates(grd) <- ~x + y
gridded(grd) <- TRUE


#Interpolating using IDW 
# ~1 setting independent variable to a constant
idw_pow1 <- idw(formula=Sea_level.mm ~ 1, locations = sea_level_sp, newdata = grd, idp = 1)

#extract sea level data 
sea_level_r <- raster(idw_pow1) #Convert interpolated data frame to raster
county <- readOGR("/home/shares/oss2017/social/DATA/counties.coast.shp") #Read in coastal county shape file
sea_level_county <- raster::extract(sea_level_r,
                                county,
                                buffer = 0.5,
                                fun = mean,
                                sp = TRUE) #Extract value for counties
sea_level_county_df <<- as.data.frame(sea_level_county)
return(sea_level_county_df)
}


sea_level_table <- data.frame() #Create an empty dataframe

#Get sea_level data for each year
list <- (1978:2016)
for (i in list){
  print(i)
  SL <- sea_level_raw[sea_level_raw$year==i,]
sea_level_table <- rbind(sea_level_table, sea_level_extract (SL))}

#Create a year column to add to the sea level table
year <- rep(list,each=60)
sea_level_table <- cbind(sea_level_table, year)
#Name the sea level column
names(sea_level_table)[18]="Sea_level.mm"
write.csv(x=sea_level_table,file="sea_level.csv")

```