Resolve #3319283 "Update readme v2"

Closes #3319283

README.md

+# 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>