Day 5 of the #30DayMapChallenge - Raster

I plotted airborne radiometric data from the Tellus survey (Geological Survey, Ireland).

Load packages:

  library(sf)
  library(tidyverse)

1. Download the radiomatric data (Tellus 2019: A5 block (Limerick)):

  dir.create("Rdata")
  Radiometric_URL <- "https://secure.dccae.gov.ie/GSI_DOWNLOAD/Geophysics/Data/GSI_Tellus_A5_RAD_GRIDS_2019.zip"
  download.file(Radiometric_URL, destfile = "Rdata/Radiometrics.zip")
  unzip(zipfile = "Rdata/Radiometrics.zip", exdir   = "Rdata/Radiometrics")
  Uranium <- rgdal::readGDAL("Rdata/Radiometrics/A5_RAD_GRIDS_2019/GXF/A5_RAD_Uranium_equivalent.gxf")

## Rdata/Radiometrics/A5_RAD_GRIDS_2019/GXF/A5_RAD_Uranium_equivalent.gxf has GDAL driver GXF 
## and has 1912 rows and 1978 columns

  # Color palette
  Col_Ramp <- readxl::read_xls("Rdata/Radiometrics/A5_RAD_GRIDS_2019/Readme_Files_And_Instructions/QGIS_Clra_32_Geosoft_hex_Colour_Ramp.xls",
                               sheet = 1,
                               col_names = FALSE,
                               skip = 4) %>%
    select(3) %>%
    as_vector() %>%
    as.character()
  unlink("Rdata", recursive = TRUE)

2. Plot the results

  breaks <- quantile(Uranium@data$band1, probs = seq(0, 1, 1/38), na.rm = TRUE)
  ggplot() + 
    inlabru::gg(data = Uranium) + 
    labs(title = "Airborne geophysical Gamma-Ray data",
         subtitle = "GSI - Tellus 2019: A5 block (Limerick)") +
    scale_fill_gradientn(name = "eU [ppm]",
                         colors = Col_Ramp,
                         values = scales::rescale(breaks),
                         limits = c(min(breaks), max(breaks))) +
    theme(legend.key.size = unit(1.5, "cm"),
          legend.key.width = unit(0.5,"cm")) +
    coord_fixed(ratio = 1)