Merge pull request #79 from springmeyer/chore/esm

chore: release v1.0.0 - ESM-only, analytical antimeridian splitting, fix antimeridian low npoints split

Author: thomas-hervey

CHANGELOG.md

@@ -5,11 +5,11 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased][unreleased]
 
-## [1.0.0] - 2026-03-29
+## [1.0.0] - 2026-04-12
 
 ### Breaking change
 
-- arc.js is now a [pure](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c) ESM package. 
+- arc.js is now a [pure](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c) ESM package (from @jgravois).
 
 If you need to `require()` arc.js as CJS (CommonJS), or have a runtime older than Node.js 18, please use `0.1.4`.
 
@@ -27,7 +27,22 @@ const gc = new GreatCircle(/* */);
 
 ### Fixed
 
-- antimeridian splitting in GreatCircle.Arc (From @copilot)
+- Antimeridian splitting in GreatCircle.Arc (from @thomas-hervey)
+
+### Changed
+
+- `GreatCircle.Arc()` now defaults to `npoints = 100` — calling `gc.Arc()` with no arguments produces a smooth 100-point arc instead of a 2-point stub
+- Antimeridian splitting now uses analytical bisection (binary search on `interpolate()`) instead of the GDAL-ported linear heuristic. This approach is more accurate, especially at high latitudes and low `npoints` values
+- `ArcOptions.offset` is now a no-op (kept for backwards compatibility); antimeridian handling is fully automatic
+
+### Removed
+
+- GDAL license file (`GDAL-LICENSE.md`). No GDAL-derived code remains in the codebase
+
+### Added
+
+- `scripts/benchmark.mjs` benchmarks bisection vs. prior linear approach across npoints and route types
+- `scripts/dump-fixtures.mjs` exports all test routes as GeoJSON for use in visual verification (such as [https://geojson.io](https://geojson.io) or the index.html demo page)
 
 ## [0.2.0] - 2025-09-22
 ### Breaking

DEVELOPING.md

@@ -6,26 +6,24 @@ This guide covers working with the TypeScript codebase for arc.js.
 
 ```bash
 npm install          # Install dependencies
-npm run build        # Build all outputs
+npm run build        # Build ESM output
 npm test             # Run TypeScript tests
-npm run test:all     # Run all tests (TypeScript + build validation)
 ```
 
 ## Project Structure
 
-```
+```text
 src/
 ├── index.ts         # Main entry point
 ├── coord.ts         # Coordinate class
-├── arc.ts           # Arc class  
+├── arc.ts           # Arc class
 ├── great-circle.ts  # Great circle calculations
 ├── line-string.ts   # Internal geometry helper
 ├── utils.ts         # Utility functions
 └── types.ts         # TypeScript type definitions
 
 test/
-├── *.test.ts        # Jest TypeScript tests (source code)
-└── build-output.test.js  # Build validation (compiled output)
+└── *.test.ts        # Jest TypeScript tests
 ```
 
 ## Development Workflow
@@ -36,14 +34,11 @@ test/
 # Run TypeScript tests (fast, for development)
 npm test
 
-# Run build validation (slower, tests compiled output)
-npm run test:build
-
-# Run everything (recommended before committing)
-npm run test:all
-
 # Watch mode for development
 npm run test:watch
+
+# Coverage report
+npm run test:coverage
 ```
 
 ### Building
@@ -52,10 +47,7 @@ npm run test:watch
 npm run build
 ```
 
-This generates:
-- `dist/` - CommonJS output with `.d.ts` files
-- `dist/esm/` - ES modules output  
-- `arc.js` - Browser bundle (UMD format)
+This generates `dist/` — ESM output with `.d.ts` declaration files.
 
 ## Publishing
 
@@ -68,7 +60,7 @@ This generates:
 
 ### Pre-publish Checklist (for maintainers)
 
-1. **Tests pass**: `npm run test:all`
+1. **Tests pass**: `npm test`
 2. **Build succeeds**: `npm run build`
 3. **Version updated**: Update `package.json` version
 4. **Changelog updated**: Document changes
@@ -77,49 +69,48 @@ This generates:
 ### Publishing Process (maintainers only)
 
 ```bash
-npm run build        # Builds automatically on prepublishOnly
-npm publish
+npm publish   # prepublishOnly runs npm run build automatically
 ```
 
-The `prepublishOnly` script ensures a fresh build before publishing.
-
 ### What Gets Published
 
-- `dist/` folder (compiled JS + TypeScript definitions)
-- `arc.js` browser bundle
+- `dist/` folder (compiled ESM JS + TypeScript definitions)
+- `src/` folder (TypeScript source files)
 - `README.md`, `LICENSE.md`, `CHANGELOG.md`
 
 ## TypeScript Development
 
 ### TypeScript Configuration
 
 - **Source**: Modern TypeScript with strict settings
-- **Output**: ES2022 for broad compatibility
-- **Paths**: `@/` alias maps to `src/` in tests
+- **Output**: ES2022, ESM only
 - **Declarations**: Full `.d.ts` generation for consumers
+
 ### Adding New Types
 
-1. Add interfaces/types to `src/types.ts`. You can see that it makes use of some GeoJSON types, but in the future it may want to use more of them.
+1. Add interfaces/types to `src/types.ts`
 2. Export public types from `src/index.ts`
 3. Import types with `import type { ... }`
-4. Add tests in relevant `test/*.test.ts` files including typescript.test.ts
-
-## Usage & Module Formats
+4. Add tests in relevant `test/*.test.ts` files including `typescript.test.ts`
 
-The package supports multiple import styles:
+## Usage
 
 ```javascript
-// CommonJS (Node.js)
-const { GreatCircle } = require('arc');
-
-// ES Modules  
+// ES Modules (Node.js or bundler)
 import { GreatCircle } from 'arc';
+```
 
-// Browser (UMD bundle)
-<script src="arc.js"></script>
+## Visual Fixture Verification
+
+To inspect all test routes as great circle arcs on a map:
+
+```bash
+npm run build                            # dist/ must exist
+node scripts/dump-fixtures.mjs | pbcopy  # macOS: copy to clipboard
 ```
 
-All formats are tested in `test/build-output.test.js`.
+Then, paste the geojson output into a visualization tool to visually verify routes, such as [geojson.io](https://geojson.io).
+**Note:** route coordinates in the script are manually updated to keep in sync with `test/fixtures/routes.ts`.
 
 ## Common Tasks
 

GDAL-LICENSE.md

@@ -9,7 +9,7 @@ Calculate great circle routes as lines in GeoJSON or WKT format.
 - Works in Node.js and browsers
 - Generates GeoJSON and WKT output formats
 - Handles dateline crossing automatically
-- Based on [Ed Williams' Aviation Formulary](https://edwilliams.org/avform.htm#Intermediate) algorithms and the GDAL source code
+- Based on [Ed Williams' Aviation Formulary](https://edwilliams.org/avform.htm#Intermediate) algorithms
 
 ## Installation
 
@@ -22,7 +22,7 @@ npm install arc
 ```js
 import { GreatCircle } from 'arc';
 const gc = new GreatCircle({x: -122, y: 48}, {x: -77, y: 39});
-const line = gc.Arc(100);
+const line = gc.Arc(); // npoints is optional, defaults to 100
 console.log(line.json()); // GeoJSON output
 ```
 
@@ -40,8 +40,8 @@ const line = gc.Arc(100);
 ```html
 <script type="module">
   import { GreatCircle } from 'https://cdn.skypack.dev/arc@1';
-  const gc = new arc.GreatCircle({x: -122, y: 48}, {x: -77, y: 39});
-  const line = gc.Arc(100);
+  const gc = new GreatCircle({x: -122, y: 48}, {x: -77, y: 39});
+  const line = gc.Arc();
 </script>
 ```
 
@@ -64,12 +64,12 @@ const gc = new GreatCircle(start, end, { name: 'Seattle to DC' });
 
 #### 3. Generate the arc
 ```js
-const line = gc.Arc(100, { offset: 10 });
+const line = gc.Arc();      // defaults to 100 points
+const line = gc.Arc(500);   // or specify a custom value
 ```
 
 **Parameters:**
-- `npoints` (number): Number of intermediate points (higher = more accurate)
-- `options.offset` (number): Dateline crossing threshold in degrees (default: 10)
+- `npoints` (number, optional): Number of intermediate points (higher = more precise, default: 100)
 
 ### TypeScript Support
 
@@ -87,8 +87,7 @@ const end: CoordinatePoint = { x: -77, y: 39 };
 const properties: RouteProperties = { name: 'Seattle to DC', color: 'blue' };
 
 const gc = new GreatCircle(start, end, properties);
-const options: ArcOptions = { offset: 10 };
-const line = gc.Arc(100, options);
+const line = gc.Arc(); // npoints is optional, defaults to 100
 
 // Fully typed return values
 const geojson = line.json(); // GeoJSONFeature
@@ -144,7 +143,7 @@ const wkt = line.wkt();
 
 ### Dateline Crossing
 
-The library automatically handles routes that cross the international dateline. The `offset` option (default: 10) controls how close to the dateline a route must be before it gets split into multiple segments. For routes near the poles, you may need a higher offset value.
+Routes that cross the international dateline are automatically detected and split into a `MultiLineString` with exact `±180°` boundary points. No configuration is needed.
 
 ## Examples
 
@@ -157,7 +156,3 @@ arc.js powers the [`greatCircle`](https://turfjs.org/docs/api/greatCircle) funct
 ## License
 
 This project is licensed under the BSD license. See [LICENSE.md](LICENSE) for details.
-
-### Third-Party Licenses
-
-This project includes code ported from GDAL (Geospatial Data Abstraction Library), which is licensed under the MIT/X11 license. See [GDAL-LICENSE.md](GDAL-LICENSE.md) for the full GDAL license text and attribution details.

README.md

@@ -333,11 +333,6 @@ <h3>Settings</h3>
                     <input type="number" id="npoints" value="100" min="10" max="1000" />
                 </div>
 
-                <div class="control-group">
-                    <label for="offset">Dateline offset (degrees):</label>
-                    <input type="number" id="offset" value="20" min="1" max="90" step="1" />
-                </div>
-
                 <div class="control-group">
                     <button id="clear" class="btn">Clear All</button>
                     <button id="reset" class="btn btn-danger">Reset View</button>
@@ -377,7 +372,6 @@ <h4>Generated GeoJSON</h4>
 
         // Configuration
         var npoints = 100;
-        var offset = 20;
         var coords = [];
         var points = [];
         var snap_tolerance = 500000;
@@ -390,10 +384,6 @@ <h4>Generated GeoJSON</h4>
             npoints = parseInt(this.value) || 100;
         });
 
-        document.getElementById('offset').addEventListener('change', function() {
-            offset = parseInt(this.value) || 20;
-        });
-
         var start, end;
 
         function draw(coords) {
@@ -469,7 +459,7 @@ <h4>Generated GeoJSON</h4>
                     };
 
                     var greatCircle = new GreatCircle(from, to, properties);
-                    var gc = greatCircle.Arc(npoints, { offset: offset });
+                    var gc = greatCircle.Arc(npoints);
                     var line = new L.geoJson().addTo(map);
                     var geojson_feature = gc.json();
 
@@ -592,7 +582,7 @@ <h4>Generated GeoJSON</h4>
 
             try {
                 var greatCircle = new GreatCircle(nyc, london, properties);
-                var gc = greatCircle.Arc(npoints, { offset: offset });
+                var gc = greatCircle.Arc(npoints);
                 var line = new L.geoJson().addTo(map);
                 var geojson_feature = gc.json();
 

index.html

@@ -1,6 +1,6 @@
 {
   "name": "arc",
-  "version": "0.2.0",
+  "version": "1.0.0",
   "description": "draw great circle arcs",
   "url": "https://github.com/springmeyer/arc.js",
   "keywords": [
@@ -14,7 +14,8 @@
   ],
   "contributors": [
     "Dane Springmeyer <dane.springmeyer@gmail.com>",
-    "John Gravois <jagravois@gmail.com>"
+    "John Gravois <jagravois@gmail.com>",
+    "Thomas Hervey <thomasahervey@gmail.com>"
   ],
   "repository": {
     "type": "git",
@@ -28,9 +29,9 @@
   },
   "files": [
     "dist/",
+    "src/",
     "README.md",
     "LICENSE.md",
-    "GDAL-LICENSE.md",
     "CHANGELOG.md"
   ],
   "engines": {