rgee example #1

rgee_example_01.R

library(mapedit) # (OPTIONAL) Interactive editing of vector data
library(raster)  # Manipulate raster data
library(scales)  # Scale functions for visualization
library(cptcity)  # cptcity color gradients!
library(tmap)    # Thematic Map Visualization <3
library(rgee)    # Bindings for Earth Engine

ee_Initialize()

## 1. Wrangling data
ee_search_dataset() %>%
  ee_search_tags("mod11a1") %>%
  ee_search_display()

dataset <- ee$ImageCollection("MODIS/006/MOD11A1")$
  filter(ee$Filter$date('2020-01-01', '2020-01-31'))$
  mean()

landSurfaceTemperature <- dataset$
  select("LST_Day_1km")$
  multiply(0.02)$
  subtract(273.15)


# landSurfaceTemperature <- dataset %>% 
#   ee$Image$select("LST_Day_1km") %>% 
#   ee$Image$multiply(0.02) %>% 
#   ee$Image$subtract(273.15)


# ee_help(ee$ImageCollection$select)

## 2. Dynamic map

landSurfaceTemperatureVis <- list(
  min = -50, 
  max = 50,
  palette = cpt("grass_bcyr")
)

Map$addLayer(
  eeObject = landSurfaceTemperature,
  visParams = landSurfaceTemperatureVis,
  name = 'Land Surface Temperature'
)

Map$addLayer(
  eeObject = landSurfaceTemperature,
  visParams = landSurfaceTemperatureVis,
  name = 'Land Surface Temperature'
) %>% editMap() -> my_polygon

## 3. Static map
geometry <- ee$Geometry$Rectangle(
  coords = c(-180,-90,180,90),
  proj = "EPSG:4326",
  geodesic = FALSE
)

world_temp <- ee_as_thumbnail(
  image = landSurfaceTemperature,  # Image to export
  region = geometry, # Region of interest
  dimensions = 1024, # output dimension
  raster = TRUE, # If FALSE returns a stars object. FALSE by default
  vizparams = landSurfaceTemperatureVis[-3] # Delete the palette element
)

min_lst <- landSurfaceTemperatureVis$min
max_lst <- landSurfaceTemperatureVis$max
world_temp[] <- scales::rescale(
  getValues(world_temp), c(min_lst, max_lst)
)

data("World") # Load world data (available after load tmap)
world_temp_robin <- projectRaster(
  from = world_temp,
  crs = crs(World)
) %>% mask(World)

tm_shape(shp = world_temp_robin) +
  tm_raster(
    title = "LST (°C)",
    palette = cpt("grass_bcyr", n = 100),
    stretch.palette = FALSE,
    style = "cont"
  ) +
  tm_shape(shp = World) + 
  tm_borders(col = "black", lwd = 0.7) +
  tm_graticules(alpha=0.8, lwd = 0.5, labels.size = 0.5) +
  tm_layout() +
  tmap_style(style = "natural") +
  tm_layout(
    scale = .8,
    bg.color = "gray90",
    frame = FALSE,
    frame.lwd = NA,
    panel.label.bg.color = NA,
    attr.outside = TRUE,
    main.title.size = 0.8,
    main.title = "Global monthly mean LST from MODIS: January 2020",
    main.title.fontface = 2,
    main.title.position = 0.1,
    legend.title.size = 1,
    legend.title.fontface = 2,
    legend.text.size = 0.7,
    legend.frame = FALSE,
    legend.outside = TRUE,
    legend.position = c(0.10, 0.38),
    legend.bg.color = "white",
    legend.bg.alpha = 1
  ) +
  tm_credits(
    text = "Source: MOD11A1 - Terra Land Surface Temperature and Emissivity Daily Global 1km",
    size = 0.8,
    position = c(0.1,0)
  ) -> lst_tmap

tmap_save(lst_tmap, "lst_tmap.svg", width = 1865,height = 1165)

Images:

• https://user-images.githubusercontent.com/16768318/84001129-a2e7a780-a92b-11ea-9df8-639e82f21955.png
• https://user-images.githubusercontent.com/16768318/84001183-b8f56800-a92b-11ea-8f3e-c121c4981d63.png
• https://user-images.githubusercontent.com/16768318/84001249-d6c2cd00-a92b-11ea-8ce1-63dc8221bbdb.png