☀️🌧️ Sunshine + Precipitation Relief Map (R)

This project generates a high-resolution terrain map that combines:

• PRISM precipitation normals (ppt, 800m, 1991-2020)
• A sunshine proxy derived from terrain exposure (aspect + slope)
• Hillshade-based relief for topographic texture

The script builds a bivariate (rain vs. sunshine) color map, adds cartographic elements (legend, north arrow, scale bar), and exports a final PNG.

What the script does

1. Reads a boundary polygon (GeoJSON) for the target area.
2. Downloads and processes DEM terrain data for that boundary.
3. Downloads PRISM precipitation normals and clips to the same extent.
4. Normalizes/stretches both rain and sunshine layers.
5. Combines them into a bivariate color surface over shaded relief.
6. Writes a high-resolution output map to outputs/.

Quick start

1. Put your boundary file in data_raw/boundary/ (GeoJSON).
2. Open sdTerra.R and set top-level options if needed (area_name, output path, etc.).
3. Run:

source("sdTerra.R")

Inputs

• Boundary: data_raw/boundary/*.geojson
• Optional labels CSV (if used): columns name, lon, lat

Required R packages

• sf
• terra
• elevatr
• ggplot2
• prism

Install once with:

install.packages(c("sf", "terra", "elevatr", "ggplot2", "prism"))