Where2

Introduction

Where2 turns static GeoJSON files into queryable APIs. Have a look at the demo application to see how it works.

Where2 is a Node.js based application, which creates APIs from GeoJSON files. Where2 supports spatial (Equals, Disjoint, Touches, Within, Overlaps, Crosses, Intersects, Contains, DistWithin) and property-based queries and returns GeoJSON. Where2 also automatically creates API docs which come with a query builder that makes it easy to get started with your queries.

Getting Started

The demo application allows you to query data from Zurich's Open Data Catalogue. Follow these instructions to set up your own instance of Where2 with datasets of your own choosing.

Prerequisites

Where2 requieres Node.js. If you don’t have it yet, go download and install Node.js.

Installing

Grab a copy of Where2, open your Terminal (or other Command Line Interface), cd into the directory and install the dependencies using npm:

npm install

To test the application run this command:

node where.js

Configuration

To use your own datasets and to make the documentation work you have to do a few changes in config.json

General Settings

• Open config.json and change host to your hostname (eg: http://localhost:33333 or https://example.herokuapp.com).
• Under docs change title and description as you like. Modify map_center and map_zoom to define the map view in the query-builder.

Datasets

All datasets are listed under data. To make a dataset available you need to define a name and an url (for hosted files) or a path (for files in the data directory).

{
	"name": "addresses",
	"url": "https://example.org/addresses.json"
}

or

{
	"name": "addresses",
	"path": "addresses.json"
}

Scheduling

Scheduling allows you to automatically update datasets periodically. To define a schedule you need to provide a cron expression. E.g. 0 3 1 * * to update at 3 am on the first of each month or 15 0 * * 3 to update every wednesday at 0:15 am.

Schema Definition

Where2 automatically detects the schema of the GeoJSON feature properties based on the first feature. Defining a custom schema instead is helpful if the properties contain stringified numbers, which could lead to unexpected results when performing queries using the less and greater than operators.

"schema": {
	"city": "TEXT",
	"street": "TEXT",
	"house-number": "INT"
}

Advanced Options

Property	Description
port	sets server port (may be overwritten by setting environment variable PORT)
data_dir	directory for local GeoJSON-files
db_name	sets the name of the SQLite database which will be created on startup

Example Configuration

{
	"host": "https://example.herokuapp.com",
	"docs": {
		"description": "My very own instance of Where2",
		"title": "My Where2",
	},
	"data": [{
		"name": "addresses",
		"url": "https://example.org/addresses.json",
		"schedule": "15 0 * * 3",
		"schema": {
			"city": "TEXT",
			"street": "TEXT",
			"house-number": "INT"
		}
	}],
	"server_port": "33333",
	"data_dir": "data/",
	"db_name": "db.db"
}

Deploy Where2 on Heroku

1. Sign in to Heroku

2. Create a new App

3. Choose an App Name and Runtime Selection

4. Switch to GitHub

5. Fork your own copy of Where2 to your account

6. Select Branch "Heroku"[^Where2 depends on node-spatialite. To get it running on Heroku we have to use the branch with compiled binaries]

7. Modify config.json to fit your needs

8. Back on Heroku choose GitHub under Deployment Method

9. Connect your GitHub Account with Heroku

10. Select the repository

11. Under Manual Deploy choose the Branch Heroku and click on Deploy Branch

12. Wait

Licence

Copyright 2016 Fidel Thomet Licensed under the MIT License.