SharedStreets Conflator

Install

$ yarn add sharedstreets-conflator

Process

1. Load LineString GeoJSON data into conflator
2. Iterate over SharedStreets Objects (only Geometry & Intersection at the moment)
3. 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

Table of Contents

• conflator
• geometry
• intersection
• reference

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