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nodeviz - Overview.wiki

Introduction

NodeViz was created because we wanted to be able to embed interactive network diagrams on a web page. Projects like GraphViz offer partial solutions for rendering networks in web-friendly formats, but don't do much to help with the interaction. After writing a few sites with custom code to build networks from a database display them, we've tried to bundle some of the functionality.

We are also usually dealing with situations where the network we are displaying is a subset of huge pile of relations stored in multiple tables in a database. This project is structured to simplify the process of converting the SQL queries into a network.

Details

NodeViz has two main parts: * Server-side code in PHP which can handle requests, assemble an appropriate network based on parameters, and render it using GraphViz

  • Client-side code in JavaScript which can request a graph from the server, insert an SVG (or JPEG) image of the graph into the DOM, render the graph data as a list, and handle selecting and zooming events.

Features

  • The network is embedded in the page as SVG, and is part of the web page DOM. This means that it can be styled using CSS!

  • Graceful degradation to non-SVG browsers. When you view with IE 7 or 8 (which cannot display inline SVG, the network image is displayed as an image with an imagemap and events should still work.

  • Networks can be rendered as both graphs and lists, with synchronized interaction between them.

  • Networks can be cached on the server to avoid repeating the expensive network layout process, an for cases where GraphViz can't be installed on the production server..

  • A structured template for assembling a network from an arbitrary data source (usually a database).

  • AJAX callbacks for sending the client additional data associated with nodes or edges.

  • Supports multiple node types (i.e 'classes') and edge types for constructing multi-partite graphs and handling interaction and list construction appropriately.

  • Zooming and panning the network in the browser, including zoomToNode methods. Can also apply zoomLevel classes to elements to selectively hide and reveal as zoom levels change.

Dependencies

Note that it is possible to deploy on a server that doesn't have GraphViz by generating pre-cached data files..

What NodeViz does not do

  • Network analysis (try Gephi, the R network library, Pajek, etc)
  • Its not the simplest way to throw up a basic network image on the web. Depending on your use case, you might want to checkout some of these alternatives: