In JaceInnis/RGEEtools: Ocean data functions for rgee

knitr::opts_chunk$set(
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RGEEtools

The goal of RGEEtools is to create easy harvesting of gee data and convert it to formats compatible with other r packages (like ggplot2). The focus data source for these function is the hycom numerical model but other sources (such as MODIS) are an object for future versions.

Installation

You can install the development version of RGEEtools from GitHub with:

# install.packages("devtools")
devtools::install_github("JaceInnis/RGEEtools")

Example

This is a basic example which shows you how to extract hycom data into a tidy datafram:

library(RGEEtools)
start()

#rgee should be already initialized 

# creates the gee geometry object necessary for any spacial query, The format of the string is copied and pasted from the gee gui. 
ROI = ROI("[-99, 31], [-99, 18], [-80, 18], [-80, 31]")

# obtains a 5 day average, the forward interval being 2001-09-28 at a resolution of 30,000 meters within the region of interest. 
list = wvtolist(ROI = ROI, date = "20180805", interval = 5, scale = 30000, depth = 0)

#converts the ree list to a r dataframe
df = geetodf(list)

head(df)

Now that we have a tidy data frame, we can visualize our data using some typical ggplot operations.

# plots the results in a raster from ggplot
ggplot(df, aes(lon, lat)) +
  geom_raster(aes( fill = velocity_u_0))

We can utilize some other functions in the package as well as some tidyverse functions to make more complicated plots

tis = ssetolist(ROI = ROI, date = "20180805", interval = 5, scale = 30000)

df2 = geetodf(tis)

df = inner_join(df, df2)


awr = thin(df, 2) # A function that would limit the number of drawn arrows by 2



ggplot(df, aes(lon, lat)) +
  geom_raster(aes( fill = surface_elevation), interpolate=TRUE)+
  geom_segment(aes(x = lon,y =  lat, xend = lon + velocity_u_0/1200, yend = lat + velocity_v_0/1200),
              size = 0.4 , arrow = arrow(length = unit(0.1,"cm")), 
              data = df[awr,] )+
  scale_fill_gradientn(colours=c("blue","green","red"))+
  borders("world", 
          xlim = c(min(df$lon), max(df$lon)), 
          ylim = c(min(df$lat), max(df$lat)),
          fill = "dark green") +
  coord_fixed(xlim = c(min(df$lon), max(df$lon)),
              ylim = c(min(df$lat), max(df$lat)))+
  theme(legend.position="none")