scripts/make_countries.js

#!/usr/bin/env node
/*
 * Copyright 2023 Uber Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/** @file make_countries.js
 * @brief Script to make country test fixtures based on Natural Earth data.
 *        This makes the fixture with polygonToCells benchmarks.
 */

const fs = require('fs');
const path = require('path');
const https = require('https');

// Using GeoJSON version as it is easy to convert
const SOURCE_URL = 'https://raw.githubusercontent.com/nvkelso/natural-earth-vector/master/geojson/ne_50m_admin_0_countries.geojson';
const TARGET = process.argv[2];

// Use Node HTTPS module for download, to avoid dependencies
function getSource(url) {
  return new Promise((resolve, reject) => {
    https.get(url, (resp) => {
      let data = '';
      resp.on('data', (chunk) => {
        data += chunk;
      });
      resp.on('end', () => {
        resolve(data);
      });
    }).on('error', reject);
  });
}

function degsToRads(deg) {
    return (deg * Math.PI) / 180;
}

function formatCoord([lng, lat]) {
  return `{${degsToRads(lat)}, ${degsToRads(lng)}}`;
}

function formatGeoLoop(loop) {
  return `{
    .numVerts = ${loop.length},
    .verts = (LatLng[]) {
      ${loop.map(formatCoord).join(',\n')}
    }
  }`
}

function formatGeoPolygon(poly, {i, name, verts}) {
  const holes = poly.slice(1);

  return `
  // ${i}. ${name} (${verts} verts)
  {
    .geoloop = ${formatGeoLoop(poly[0])},
    .numHoles = ${holes.length}${holes.length ? `,
    .holes = (GeoLoop[]) {
      ${holes.map(formatGeoLoop).join(',\n')}
    }` : ''}
  }`
}

async function makeCountries(sourceUrl, targetPath) {
  console.log(`Downloading from ${sourceUrl}...`)
  const countriesJson = await getSource(sourceUrl);
  const countries = JSON.parse(countriesJson);

  console.log(`Download completed, found ${countries.features.length} countries`);

  const polygons = [];
  const names = [];

  let i = 0;

  for (const {geometry, properties: {ADMIN: name}} of countries.features) {
    if (geometry.type === 'Polygon') {
      polygons.push(geometry.coordinates);
      names.push({i: String(i++), name, verts: geometry.coordinates[0].length});
    } else if (geometry.type === 'MultiPolygon') {
      for (const poly of geometry.coordinates) {
        polygons.push(poly);
        names.push({i: String(i++), name, verts: poly[0].length});
      }
    }
  }

  console.log(`Found ${polygons.length} polygons`);

  // In order to only allocate memory once, we take the biggest size
  // at res 7, pad it, and size up based on powers of 7. This number was
  // empirically determined.
  const MAX_SIZE_RES_7 = 17544338;

  const out = `/*
 * Copyright 2023 Uber Technologies, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * This file is generated by scripts/make_countries.js.
 * Made with Natural Earth. Contains data from nvkelso/natural-earth-vector.
 * https://github.com/nvkelso/natural-earth-vector/blob/ca96624a56bd078437bca8184e78163e5039ad19/LICENSE.md
 */

#include "benchmark.h"
#include "h3api.h"
#include "mathExtensions.h"
#include "polyfill.h"
#include "polygon.h"

const GeoPolygon COUNTRIES[${polygons.length}] = {${
  polygons.map((poly, i) => formatGeoPolygon(poly, names[i])).join(',')
}};

BEGIN_BENCHMARKS();

int MAX_RES = 5;
int64_t numHexagons;
H3Index *hexagons;

for (int res = 0; res < MAX_RES + 1; res++) {

  printf("Res %d", res);

  BENCHMARK(polygonToCells_AllCountries1, 5, {
    for (int index = 0; index < ${polygons.length}; index++) {
      H3_EXPORT(maxPolygonToCellsSize)(&COUNTRIES[index], res, CONTAINMENT_CENTER, &numHexagons);
      hexagons = calloc(numHexagons, sizeof(H3Index));
      H3_EXPORT(polygonToCells)(&COUNTRIES[index], res, CONTAINMENT_CENTER, hexagons);
      free(hexagons);
    }
  });

  BENCHMARK(polygonToCells_AllCountries2, 5, {
    for (int index = 0; index < ${polygons.length}; index++) {
      H3_EXPORT(maxPolygonToCellsSizeExperimental)(&COUNTRIES[index], res, CONTAINMENT_CENTER, &numHexagons);
      hexagons = calloc(numHexagons, sizeof(H3Index));
      H3_EXPORT(polygonToCellsExperimental)(&COUNTRIES[index], res, CONTAINMENT_CENTER, numHexagons, hexagons);
      free(hexagons);
    }
  });

  BENCHMARK(polygonToCells_AllCountries3, 5, {
    for (int index = 0; index < ${polygons.length}; index++) {
      H3_EXPORT(maxPolygonToCellsSizeExperimental)(&COUNTRIES[index], res, CONTAINMENT_CENTER, &numHexagons);
      hexagons = calloc(numHexagons, sizeof(H3Index));
      H3_EXPORT(polygonToCellsExperimental)(&COUNTRIES[index], res, CONTAINMENT_FULL, numHexagons, hexagons);
      free(hexagons);
    }
  });

  BENCHMARK(polygonToCells_AllCountries4, 5, {
    for (int index = 0; index < ${polygons.length}; index++) {
      H3_EXPORT(maxPolygonToCellsSizeExperimental)(&COUNTRIES[index], res, CONTAINMENT_CENTER, &numHexagons);
      hexagons = calloc(numHexagons, sizeof(H3Index));
      H3_EXPORT(polygonToCellsExperimental)(&COUNTRIES[index], res, CONTAINMENT_OVERLAPPING, numHexagons, hexagons);
      free(hexagons);
    }
  });

}


END_BENCHMARKS();
  `

  fs.mkdirSync(path.dirname(targetPath), { recursive:true });
  fs.writeFileSync(targetPath, out, 'utf-8');

  console.log(`Wrote fixture to ${targetPath}`);
}

makeCountries(SOURCE_URL, TARGET);