Crate surtgis_relief 

SurtGIS Relief

Rayshader-style shaded-relief compositing on top of the terrain primitives that already live in surtgis-algorithms. This crate is a compositor, not a new set of algorithms — see SPEC_SURTGIS_RELIEF.md in the repository root for the full design.

What lives here

• ray_shade — ray-traced cast shadows via surtgis_algorithms::terrain::horizon_angle_map_fast, with optional soft-shadow averaging over multiple sun samples.
• sphere_shade — normal-based hillshade as an intensity layer in [0, 1], wrapping surtgis_algorithms::terrain::hillshade.

What is re-exported

Pixel-buffer and PNG output live in surtgis_colormap; we re-export the relevant types at the crate root for ergonomics.

use surtgis_relief::{ray_shade, sphere_shade, RayShadeParams, SunSample, RgbaImage};

let shadow_mask = ray_shade(&dem, &RayShadeParams::default())?;
let mut img = RgbaImage::from_intensity(&sphere_shade(&dem, Default::default())?);
let shadow_layer = RgbaImage::from_intensity(&shadow_mask);
img.multiply(&shadow_layer, 0.5)?;
img.save_png("relief.png")?;

Structs

ColormapParams

Parameters for colormap rendering.

RayShadeParams

Parameters for ray_shade.

ReliefBuilder

Order-preserving accumulator for relief layers.

RgbaImage

Row-major 8-bit RGBA pixel buffer.

SunSample

A single sun position.

WaterParams

Parameters for detect_water.

Enums

ColorScheme

Available color schemes.

EncodeError

ReliefError

Errors produced by the relief crate.

Functions

ambient_shade

Compute the ambient-occlusion intensity layer.

cast_shadow_ray_mask

Per-cell binary shadow mask: 1.0 = lit, 0.0 = in shadow.

detect_water

Detect water bodies as large flat connected components.

horizon_tan_map

Per-cell maximum tan(angle_to_occluder) along a single azimuth.

ray_shade

Ray-traced cast shadows.

rgba_to_png_bytes

Encode an arbitrary RGBA byte buffer as PNG. Native target only.

save_png

Write an RGBA buffer to path as a PNG. Native target only.

sphere_shade

Normal-based hillshade as intensity in [0, 1].

water_depth

Compute per-cell water depth from a binary water mask. Returns a Raster<f32> where every water cell holds its 8-connected Chebyshev distance (in cells) to the nearest non-water neighbour. Shore cells → 1.0, deepest centres of large lakes → large values. Non-water cells return 0.0.

Type Aliases

Result

Result alias scoped to this crate.