Resolve #3319283 "Update readme v2"

# Views GeoJSON

## Table of contents

- Summary

- Requirements

- Installation

- Usage

    - Bounding Box Support

- To Do

- Credits

- Current Maintainers

## Summary

Views GeoJSON is a style plugin for Views to deliver location-specific data in GeoJSON format, see [RFC 7946: The GeoJSON Format](view-source:https://www.rfc-editor.org/rfc/rfc7946).

Each row is output as a GeoJSON "Features" including geospatial data and optional metadata. All features are wrapped in a "Feature Collection" object.

## Requirements

Drupal core modules

- Views

- RESTful Web Services

- Serialization

External projects

- [itamair/geophp](https://packagist.org/packages/itamair/geophp)

Optional Drupal modules

- [Geofield](https://www.drupal.org/project/geofield)

- [Geolocation](https://www.drupal.org/project/geolocation)

## Installation

Install as you would normally install a contributed Drupal module.

Visit https://www.drupal.org/node/1897420 for further information.

## Usage

1. Create a View with content containing geospatial data

1. Add a "GeoJSON export" display

1. Add fields to output a Geofield, Geolocation, longitude & latitude or WKT

1. Optionally add fields for name and description

1. Set Format for the display to "GeoJSON"

1. In the "Settings" for this format:

    - Choose Map Data Source (Other: Lat/Lon Point, Geofield, etc.)

    - Assign the field(s) that represent Latitude and Longitude

    - Optionally choose fields representing Title and Description for each point

    - Optionally set a JSONP prefix, (see https://en.wikipedia.org/wiki/JSONP)

1. If using with the OpenLayers module, your new GeoJSON layer will be

    available as an Overlay layer on the "Layers & Styles" tab when editing your map

### Bounding Box Filtering

GeoJSON views can accept a bounding box as an argument to return only the points

within that box.

It has been tested with OpenLayers' Bounding Box Strategy but should work with

any mapping tool that requests bounding box coordinates as

"?bbox=left,bottom,right,top" in the query string. Argument ID "bbox" is

default for OpenLayers but can be changed.

1. Create a GeoJSON view as above in USAGE

1. Add a layer to OpenLayers of type GeoJSON, at

`/admin/structure/openlayers/layers/add/openlayers_layer_type_geojson`,

specifying the URL to your GeoJSON feed and checking the box for "Use Bounding

Box Strategy"

1. In your GeoJSON View configuration, add a Contextual Filter of type:

"Custom: Bounding box"

1. In the Contextual Filter settings, under "When the filter value is NOT in

the URL as a normal Drupal argument", choose: "Provide default value"

1. In the "Type" dropdown, choose: "Bounding box from query string"

1. For OpenLayers, leave "Query argument ID" as "bbox" and click Apply

## To Do

- Support addditional GeoJSON feature types like LineString

- Support an optional altitude coordinate for Point positions

- Support additional coordinate systems

## Credits

This module was originally born from a patch by tmcw to the

[OpenLayers module](https://drupal.org/node/889190#comment-3376628) and adapted

to model the

[Views Datasource module](https://drupal.org/project/views_datasource).

Much of the code is drawn directly from these sources.

## Current Maintainers

- Jeff Schuler (jeffschuler) - <https://www.drupal.org/u/jeffschuler>

CONTENTS OF THIS FILE

---------------------

* Summary

* Requirements

* Installation

* Usage

  * Bounding Box Support

* To Do

* Credits

* Current Maintainers

SUMMARY

-------

Views GeoJSON is a style plugin for Views to deliver location-specific data in GeoJSON format, (see GeoJSON spec: http://geojson.org/geojson-spec.html).

Each row is output as a GeoJSON "Features" including geospatial data and optional metadata. All features are wrapped in a "Feature Collection" object.

REQUIREMENTS

------------

Drupal modules:

* Views

* Serialization

* Rest

Optional Drupal modules:

* Geofield 8.x-1.0-alpha2 or greater

INSTALLATION

------------

Install the module as usual.

See https://www.drupal.org/node/1897420 for help installing Drupal 8 modules.

USAGE

-----

1. Create a View with a Feed display on content with geospatial data.

2. Add fields to output a Geofield, longitude & latitude or WKT.

3. Optionally add fields for name and description.

4. Set Format for the display to "GeoJSON Feed".

5. In the "Style options" for this format:

  * Choose Map Data Source (Other: Lat/Lon Point, Geofield, etc.)

  * Assign the fields that represent Latitude and Longitude.

  * Optionally choose fields representing name and description for each point.

  * Optionally set a JSONP prefix, (see http://en.wikipedia.org/wiki/JSONP).

  * Set the Content-type header to be sent. The default is "application/json",

    the standard MIME type for JSON, per http://www.ietf.org/rfc/rfc4627.txt.

6. If using with the OpenLayers module, your new GeoJSON layer will be available

  as an Overlay layer on the "Layers & Styles" tab when editing your map.

Bounding Box Filtering

--------------------

GeoJSON views can accept a bounding box as an argument to return only the

points within that box.

It has been tested with OpenLayers' Bounding Box Strategy but should work

with any mapping tool that requests bounding box coordinates as

"?bbox=left,bottom,right,top" in the query string. Argument ID "bbox" is

default for OpenLayers but can be changed.

OpenLayers 7.x-2.x-dev is currently required for OpenLayers BBOX integration.

See OpenLayers issue http://drupal.org/node/1493344, "Support BBOX strategy in

the GeoJSON layer type".

1. Create a GeoJSON view as above in USAGE.

2. Add a layer to OpenLayers of type GeoJSON, at

   admin/structure/openlayers/layers/add/openlayers_layer_type_geojson,

   specifying the URL to your GeoJSON feed and checking the box for "Use

   Bounding Box Strategy".

3. In your GeoJSON View configuration, add a Contextual Filter of type:

   "Custom: Bounding box".

4. In the Contextual Filter settings, under "When the filter value is NOT in

   the URL as a normal Drupal argument", choose: "Provide default value".

5. In the "Type" dropdown, choose: "Bounding box from query string".

6. For OpenLayers, leave "Query argument ID" as "bbox" and click Apply.

TO DO

-----

* Support addditional GeoJSON feature types like LineString.

* Support an optional altitude coordinate for Point positions.

* Support additional coordinate systems.

CREDITS

-------

This module was originally born from a patch by tmcw to the OpenLayers module

(http://drupal.org/node/889190#comment-3376628) and adapted to model the Views

Datasource module (http://drupal.org/project/views_datasource).

Much of the code is drawn directly from these sources.

CURRENT MAINTAINERS

-------------------

* jeffschuler - http://drupal.org/user/239714