trifeather/project.js

Pre-triangulated feather files

#!/usr/bin/env node

import TriFeather from "./src/TriFeather.js";
import { random_points } from "./src/RandomPoints.js";
import JSONStream from "JSONStream";
import * as d3geo from "d3-geo";
import * as geoproj from "d3-geo-projection";
import * as geoAlbersUsaTerritories from "./src/geo-albers-usa-territories.js";
import pkg from "commander";
import { tableToIPC } from "apache-arrow";

const { program } = pkg;

const projections = {
  albersUsa: geoAlbersUsaTerritories,
  mollweide: d3geo.geoMollweide,
  mercator: d3geo.geoMercator,
};

program.version("1.1.1");

program
  .option(
    "-c, --counts [counts...]",
    "Count fields to use for dot-density; must be keys in the geojson properties"
  )
  .option(
    "-n, --names [names...]",
    `Column names to split count fields into using delimiter. E.g., {'white_non-hispanic': 31}
  with names ['race', 'ethnicity'] will add 31 points with "race" of "white" and "ethnicity" of "non-hispanic." If left blank, 
  the column will be named "category" and no splitting will occur.`
  )
  .option(
    "-d, --delimiter <delimiter>",
    `Delimiter character. in conjunction with names. Default "_" if more than one "names" passed.`
  )
  .option(
    "-k, --keep [keep...]",
    "Geojson properties to pass into derived points without alteration. (Saved as utf8 regardless of type.)"
  )
  .option(
    "-p --projection <projection>",
    "Projection. String representing d3-geo or d3-geo-projection factory function. Will be scaled up by a factor of 1e12 to support zoom.",
    "geoAlbersUsaTerritories"
  )
  .requiredOption("-f, --files <files...>", "geojson files to parse");

program.parse(process.argv);
// Look in several places.
const proj =
  d3geo[program.projection] ||
  geoAlbersUsaTerritories[program.projection] ||
  geoproj[program.projection];

console.log(proj);
const projection = proj().scale(1);

import fs from "fs";

const fnames = program.opts()["files"];
const counts = program.opts()["counts"];
const names = program.opts()["names"] || ["category"];
const delimiter =
  program.opts()["delimiter"] || names.length == 1
    ? "ARBITRYAR STRING_THAT_WONT_OCCURR IN TEXT"
    : "_";
const keep = program.opts()["keep"] || [];

for (let fname of fnames) {
  console.log(fname);
  if (!(fname.endsWith(".json") || fname.endsWith(".geojson"))) {
    throw "Suffix should be 'json' or 'geojson', but " + fname + " found";
  }

  const destname = fname
    .replace(".geojson", counts ? ".feather" : ".trifeather")
    .replace(".json", counts ? ".feather" : ".trifeather");

  if (fs.existsSync(destname)) {
    console.log("Skipping " + destname + " because it already exists");
    continue;
  }

  /*var data = fs.readFileSync(fname, 'utf-8');
  console.log(fname, "loaded")
  const feature_collection = JSON.parse(data)
  */

  let stream = fs.createReadStream(fname, { encoding: "utf8" });
  let parser = JSONStream.parse("$*");
  stream.pipe(parser);

  let feature_collection_promise = new Promise((resolve, reject) => {
    let d = {};
    parser
      .on("data", (data) => {
        d[data.key] = data.value;
      })
      .on("end", () => {
        // I don't really get streaming in node, so I'm wrapping
        // it in a promise.
        resolve(d);
      });
  });

  const feature_collection = await feature_collection_promise;

  console.log(fname, "parsed... Creating triangulation");

  let trifeather = TriFeather.from_feature_collection(
    feature_collection,
    projection
  );
  console.log(fname, "triangulated");

  let t;
  if (!counts) {
    t = trifeather.t;
  } else {
    t = random_points(trifeather, counts, 1, "feather", keep, names, delimiter);
  }
  let b = Buffer.from(tableToIPC(t, "file"));
  const fd = fs.openSync(destname, "w");
  fs.writeSync(fd, b);
}