Sharedstreets-conflator NPM

SharedStreets Conflator

Install

$ yarn add sharedstreets-conflator

Process

Load LineString GeoJSON data into conflator
Iterate over SharedStreets Objects (only Geometry & Intersection at the moment)
Manipulate Conflator Objects by using data, type, tile components.

SharedStreets Objects are streamed as each individual LineString is being processed.

Example - CLI

Install CLI globally

$ yarn global add sharedstreets-conflator

terminal

Usage:
  $ sharedstreets-conflator <filepath>

Options:
  -o, --out <folder>      output folder name (default: "./")
  --zoom                  zoom level given to calculate the ZXY tiles (default: 12)

Examples:
  $ sharedstreets-conflator "example.shp" --out "./data"

The example Shapefile will not produce tiles in JSON format in the desired ./data folder.

./data/example.12-1144-1494.geometry.json
./data/example.12-1144-1494.intersection.json
./data/example.12-1144-1494.reference.json

Example - Javascript/Node

import conflator from 'sharedstreets-conflator';
import {lineString} from '@turf/helpers';

// Load custom GeoJSON data (Feature<LineString> or FeatureCollection<LineString>)
const geojson = lineString([[-76, 40], [-75, 38]]);

for (const value of conflator(geojson)) {
  console.log(value);
  value.data // => SharedStreets Object (Geometry | Intersection | Reference)
  value.type // => SharedStreets Type as String ("geometry", "intersection", "reference")
  value.tile // => XYZ Tile (ex: [180, 220, 12])
}

Another syntax approach when handling ES6 Iterators:

const iterator = conflator(geojson);
while (true) {
  const {value, done} = iterator.next();
  if (done) { break; }
  value.data // => SharedStreets Object (Geometry | Intersection | Reference)
  value.type // => SharedStreets Type as String ("geometry", "intersection", "reference")
  value.tile // => XYZ Tile (ex: [180, 220, 12])
}

Output

Convert Shapefile to GeoJSON

With NodeJS we can convert an ESRI Shapefile with mbostock/shapefile to GeoJSON.

Install shapefile

$ yarn global add shapefile

Using NodeJS/Javascript

import * as shapefile from "shapefile";

shapefile.read("example.shp").then(geojson => {
  // SharedStreets Conflator inputs GeoJSON LineString FeatureCollection
});

Or via terminal (CLI)

$ shp2json --help

  Usage: shp2json [options] [file]

  Convert a Shapefile to GeoJSON.


  Options:

    -V, --version            output the version number
    -o, --out <file>         output file name; defaults to “-” for stdout (default: -)
    -n, --newline-delimited  output newline-delimited JSON
    -g, --geometry           output geometries (implies --ignore-properties)
    --ignore-properties      don’t read shapefile properties (.dbf)
    --encoding <encoding>    character encoding for shapefile properties (.dbf)
    --crs-name <name>        specify a named CRS for the output feature collection
    -h, --help               output usage information

$ shp2json example.shp --out example.geojson

Typescript Config

tsconfig.json (target must equal ES6)

{
  "compilerOptions": {
    /* Basic Options */
    "target": "es6",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */

    /* Strict Type-Checking Options */
    "strict": true,                           /* Enable all strict type-checking options. */

    /* Module Resolution Options */
    "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
  }
}

Considerations

Streaming Data using Iterators.
Saving Tilesets using xyz tile pattern.
FeatureCollection sets up a processing queue.
Atomic actions piped into a message queue.
stream queues need to spill to disk at various points in the process
Memory requirements to cache intermediate products
AWS message queues that buffer between lambdas processing the data
self-contained operation

API

conflator

SharedStreets Conflator

Parameters

geojson (Feature<LineString> | FeatureCollection<LineString>) GeoJSON LineString Feature/FeatureCollection
options Object Optional Parameters (optional, default {})
- options.zoom number Zoom level given to calculate the ZXY tiles (optional, default 12)

Examples

import { lineString } from "@turf/helpers";
import * as sharedstreetsConflator from "sharedstreets-conflator";

// GeoJSON Data
const geojson = lineString([[110, 45], [115, 50], [120, 55]]);

// Iterate over SharedStreets Objects
for (const value of sharedstreetsConflator.conflator(geojson, {zoom: 12})) {
  value.data // => SharedStreets Object (Geometry | Intersection | Reference)
  value.type // => SharedStreets Type as String ("geometry", "intersection", "reference")
  value.tile // => XYZ Tile (ex: [180, 220, 12])
}

Returns IterableIterator<(ConflatorGeometry | ConflatorIntersection)> Iterator of SharedStreets Objects

geometry

Process Geometry

Parameters

feature Feature<LineString> GeoJSON LineString Feature
options (optional, default {zoom:12})

Examples

import { lineString } from "@turf/helpers";
import * as sharedstreetsConflator from "sharedstreets-conflator";

const feature = lineString([[110, 45], [115, 50], [120, 55]]);

for (const geom of sharedstreetsConflator.geometry(feature, {zoom: 12})) {
  geom; // => SharedStreetsGeometry
}

Returns IterableIterator<SharedStreetsGeometry> SharedStreetsGeometry Iterator

intersection

Process Intersection

Parameters

feature Feature<LineString> GeoJSON LineString Feature
options (optional, default {zoom:12})

Examples

import { lineString } from "@turf/helpers";
import * as sharedstreetsConflator from "sharedstreets-conflator";

const feature = lineString([[110, 45], [115, 50], [120, 55]]);

for (const intersect of sharedstreetsConflator.intersection(feature, {zoom: 12})) {
  intersect; // => SharedStreetsIntersection
}

Returns IterableIterator<SharedStreetsIntersection> SharedStreetsIntersection Iterator

reference

Process Reference

Parameters

feature Feature<LineString> GeoJSON LineString Feature
options (optional, default {zoom:12})

Examples

import { lineString } from "@turf/helpers";
import * as sharedstreetsConflator from "sharedstreets-conflator";

const feature = lineString([[110, 45], [115, 50], [120, 55]]);

for (const ref of sharedstreetsConflator.reference(feature, {zoom: 12})) {
  ref; // => SharedStreetsReference
}

Returns IterableIterator<SharedStreetsRefrence> SharedStreetsReference Iterator