Calculate 360-degree horizon elevation angles from GeoTIFF elevation data.

Requirements

- Node.js 22+
- GDAL (brew install gdal / apt install gdal-bin)

Install

``bash
npm install @bridgerb/horizon gdal-async
`

Usage

`typescript
import { loadElevationData } from "@bridgerb/horizon";

const elevation = await loadElevationData("path/to/elevation.tif");

const horizon = elevation.calculateHorizon(40.311259, -111.659330);
// Returns 360 results, one per degree

const partial = elevation.calculateHorizon(40.311259, -111.659330, 45, 135);
// Only directions 45° to 135°
`

API

$3

Loads a GeoTIFF elevation file. Call once, then query many times.

$3

- lat - Latitude in degrees
- lng - Longitude in degrees
- start - Start direction (default: 0)
- end - End direction (default: 359)

$3

- direction - Compass direction in degrees (0 = North)
- elevationAngleDegrees - Angle to horizon
- distance_km` - Distance to horizon point

License

Unlicense - Public Domain