Gephi 0.9 released: Play with network data again

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We’re proud to announce the release of the next major version of Gephi! This 0.9.0 version has been more than three years in the making but today brings an exciting new life to this project, and the graph/network analytics community at large. You can download it here for Windows, Mac OS X and Linux.

Gephi is the leading graph visualization software – known as the “Photoshop for networks” and is open-source and free. It has been downloaded more than a million times and is used by many scholars and data scientists around the world. This new release brings new features in the area of dynamic networks (i.e. network over time) and major compatibility and performance improvements.

Since the last release in 2013, users were facing compatibility issues with Java, which have been resolved with this release. Development had slow down three years ago but had never stopped. In fact, in March 2013 the time had come to think about what Gephi 1.0 would look like and realize it needed a new core. This was by far the most complex project the team had to overcome but developers had a long-term vision and know that future developments will now rely on a robust and extensible core, with world-class performances.

The world is increasingly complex and interconnected. Gephi’s purpose is to unfold this complex relational data in a way anyone can understand them. It allows you to visualize graph data as a map and create the visualizations to support your narratives. State-of-the-art algorithms make readable layouts, highlighting communities or influential nodes. Visual tools tweak colors and shapes to reveal hidden patterns in the data, helping solving complex problems. More and more network-maps are pictured in online, offline press and other communication media. They spread from science to business, art and activism. People are increasingly exposed to them and learn how to read them. Gephi aims to accelerate this commoditization process by providing free and easy-to-use tools.

What’s new in Gephi 0.9?

The list is too long! The complete changelog for this version can be found on GitHub’s release page.

Next steps

There are a few immediate next steps coming up right after this release. Following-up on the recent plugin development announcement we’ll get in touch with plugin developers and start migrating plugins to this version. There’s more than 80 plugins to update!

Then, we’ll identify and resolve new issues that appeared with this version. A future Gephi 0.9.1 release will come next year to address those.

A Gephi Toolkit release will also be made very soon so developers can update their application built on top of Gephi’s modules. In the meantime, we’re interested in users’ feedback and want to hear from you on Twitter or Facebook. Issues can directly be reported on GitHub as well, where the developers are.

Finally, thanks to all contributors and the community for supporting this project!

Plugin development gets new tools and opens-up to the community

Since the introduction of the Gephi Marketplace and tools such as the Plugins Bootcamp we’ve seen more and more plugins being developed. Even developers with little experience with Java give it a try and succeed in creating their first plugin. We want developers to be productive and make it as easy as possible to get started with plugin development and find help along the way. As the release of the 0.9 version is near, it’s time to review our plan on that matter and upcoming improvements. Here’s the summary:

  • The gephi-plugins base repository (i.e. repository plugin developers fork) is now using Maven for building and is simpler. It contains only 4 files versus 890 for the Ant-based system.
  • All Gephi modules are published on Maven central, making it very easy to inspect and extend.
  • Introduction of a custom Maven plugin designed to facilitate plugin development.
  • The submission and review of plugins will be entirely based of GitHub, making it more scalable and transparent.
  • A new online portal for plugins is coming up with an easier edit experience and new features.

From Ant to Maven

Before diving into plugins, let’s first review what has changed on how Gephi is compiled, built and packaged – as this directly affects plugins as well. Since the Gephi 0.8.2 version we have migrated our build system from Ant to Maven. This is in line with what the Netbeans Platform (i.e. which Gephi is based on) community recommends. It already has increased the level of automation we’re capable of as a result. The main benefits are (compared to Ant):

  • Maven is great at dependencies management. It’s now very clear what version of what library Gephi depends on, making it simpler to integrate. Dependencies are also downloaded automatically instead of being checked in the codebase
  • Unlike the Ant-based system, it’s independent from Netbeans. This allows developers not using Netbeans to develop Gephi and produce a build entirely from the command-line.
  • Gephi modules can now be placed on Maven Central (i.e. global repository where Maven finds its dependencies). This allows plugins to automatically find the Gephi dependencies online, reducing the manual steps at each Gephi upgrade.

Build assistant

There are a few critical steps we want to help plugin developers with and as a result started the development of a custom Maven plugin. This new tool will work behind the scenes when developers build their plugin. No installation or configuration is needed as it comes already as dependency of the gephi-plugins module. It already addresses common pain points and hope to automate more and more of the steps in the future. This is what it can do as of today:

  • Plugin validation: The assistant reviews the plugin configuration and metadata at each build. This allows for instance to check if the plugin depends on the correct Gephi version or remind the developer to define an author or license in its configuration.
  • Run Gephi with plugins: A single command allows to run Gephi with the plugins pre-installed. This makes testing faster than ever when developing plugins.
  • New plugin generator: A step-by-step command-line tool that creates the correct folder structure and configuration to get started.

In the future, we want to rely on this build assistant to further automate the process and for instance do easy migration or code generation. For instance, you could ask to generate a Layout plugin code and configuration. Afterwards, all needed would be to fill in the blanks in the code.

A new way to review and submit plugins

As the number of plugins grows, it’s important to have a clear process how plugins are reviewed and updated. We also want this process to be transparent and open to the community. So far, the process was based on the submission of the plugin binaries with a manual review done by the team. This helped us get where we are today, but we want to get it to the next level and propose to entirely move this process to GitHub – using the pull-request mechanism. This has multiple advantages, listed below:

  • Reviewing new/updated plugins can scale because any developer can read the code and contribute to the pull requests.
  • Developers are already asked to fork the gephi-plugins repository so submitting the plugin via GitHub is a natural extension to it.
  • There’s a clear history of each version, comment and what code has changed from one version to another.
  • It makes it easier to test plugins and detect issues before the plugin is approved.

As part of this migration, we’ll no longer add plugins with closed source code but all existing plugins for Gephi 0.8.2 will remain available. For security and stability reasons, it’s essential that each plugin’s code can be inspected before approval. In order for this to work, all existing plugins not already on GitHub or not forking the gephi-plugins repository will need to migrate. For those already set up, the migration will be easier but Ant-based plugins will still need to migrate to Maven.

To summarize, this is what the new 4-steps process looks like for developers:

gephi-new-plugin-development-process

In the current submission process we ask for additional information such as description, author or license as well as allow the upload of images. Going forward with GitHub, all of these data will directly be defined in the plugin’s configuration making it easier to update.

A new home for plugins (again)

Plugins are currently available online from the Gephi Marketplace, where users could also reach people providing teachings and support.  We have ideas on how to improve these community services and will be migrating them to a new architecture, starting with the plugins. We will tell you more about these changes in an upcoming post but for now our focus is on developing a new lightweight plugin portal that can directly be connected with the data source on GitHub.

Here is a preview of what it will look like for plugin pages:

new-plugin-frontend-preview

 

The content of this website will be automatically updated when plugins are published or updated. The way it works is with Travis CI (i.e. continuous integration platform) simply refreshing the JSON file after changes to the plugin repository on GitHub. Developers can even embed images and write the description in Markdown. This will remove entirely the need for plugin developers to login to the marketplace, update NBMs and metadata.

Migrating plugins

This new Maven-based repository along with the new submission process will be introduced with the Gephi 0.9 release. Let’s review what plugin developers need to know to bring their plugin to this new major version.

As with all major Gephi release, plugins compatibility needs to be evaluated as APIs may have changed. In fact, given this new version is based on an entirely redeveloped core it’s very likely code changes will be required. Hopefully, these changes will often be minor and actually simplify things (i.e less, more efficient code). Documentation will be published on these API changes and core developers will be available to answer questions as well.

Plugin developers will also get contacted regarding moving their code to GitHub with a step-by-step guide. We’re considering adding a migrate command to the new Gephi Maven plugin to facilitate the transition from Ant but that’s an unfunded project at the moment (if you’re interested contributing to that, please let us know). Stay tuned for details right after the release on the path to migration.

And again, thanks for all your hard work on bringing your ideas to life though new Gephi plugins!

 

Gephi boosts its performance with new “GraphStore” core

Gephi is a graph visualization and analysis platform – the entire tool revolves around the graph the user is manipulating. All modules (e.g. filter, ranking, layout etc.) touch the graph in some way or another and everything happens in real-time, reflected in the visualization. It’s therefore extremely important to rely on a robust and fast underlying graph structure. As explained in this article we decided in 2013 to rewrite the graph structure and started the GraphStore project. Today, this project is mostly complete and it’s time to look at some of the benefits GraphStore is bringing into Gephi (which its 0.9 release is approaching).

Performance is critical when analyzing graphs. A lot can be done to optimize how graphs are represented and accessed in the code but it remains a hard problem. The first versions of Gephi didn’t always shine in that area as the graphs were using a lot of memory and some operations such as filter were slow on large networks. A lot was learnt though and when the time came to start from scratch we knew what would move the needle. Compared to the previous implementation, GraphStore uses simpler data structures (e.g. more arrays, less maps) and cache-friendly collections to make common graph operations faster. Along the way, we relied on many micro-benchmarks to understand what was expensive and what was not. As often with Java, this can lead to surprises but it’s a necessary process to build a world-class graph library.

Benchmark

We wanted to compare Gephi 0.8.2 and Gephi 0.9 (development version) so we’ve  created a benchmark to test the most common graph operations. Here is what we found. The table below represents the relative improvement between the two versions. For instance, “2X” means that the operation is twice faster to complete. A benchmarking utility was used to guarantee the measurements precision and each scenario was performed at least 20 times, and up to 600 times in some cases. We used two different classic graphs, one small (1.5K nodes, 19K edges) and one medium (83K nodes, 68K edges) . Larger graphs may be evaluated in a future blog article.

Benchmark / Graph SMALL (n=1490, e=19025) MEDIUM (n=82670, e=67851)
Node Iteration 23.0x 34.6x
Edge Iteration 40.1x 109.4x
Node Lookup 1.6x 2.1x
Edge Lookup 1.2x 2.3x
Get Edge 1.1x 1.2x
Get Degree 2.5x 2.3x
Get Neighbors 3.4x 1.2x
Set Attributes 2.3x 0.1x
Get Attributes 3.3x 4.0x
Add Nodes 6.2x 5.7x
Add & Remove Nodes 1.4x 2.9x
Add Edges 7.7x 3.8x
Add & Remove Edges 3.3x 1.8x
Create View 2851.0x 4762.3x
Iterate Nodes In View 2.7x 1.5x
Iterate Edges In View 11.6x 7.3x
Save Project 2.4x 1.7x
Load Project 0.6x 0.6x
Project File Size 1.9x 1.5x

These benchmarks show pretty remarkable improvements in common operations, especially read ones such as node or edge iteration. For instance, in average it takes 40 to 100 times less CPU to read all the edges in the graph. Although this benchmark focus on low-level graph operations it will bring material improvements to user-level features such as filter or layout. The way GraphStore creates views is different from what we were doing before, and doesn’t require a deep graph copy anymore – explaining the large difference. Finally, only the set attribute is significantly slower but that can be explained by the introduction of inverted indices, which are updated when attributes are set.

And what about memory usage? Saving memory has been one of our obsession and there’s good news to report on that front as well. Below is a quick comparaison between Gephi 0.8.2 and Gephi 0.9 for the same medium graph above.

Benchmark Gephi 0.8.2 Gephi 0.9 Improvement
Simple graph 115MB 52MB 2.2X
Graph with 5 attribute columns 186MB 55MB 3.4X

This benchmark shows a clear reduction of memory usage in Gephi’s next version. How much? It’s hard to say as it really depends on the graph but the denser (i.e. more edges) and the more attributes, the more memory saved as significant improvements have been made in these areas. Dynamic graphs (i.e. graphs that have their topology or attributes change over time) will also see a big boost as we’ve redesigned this part from scratch.

What’s next?

All of the GraphStore project benefits are included in the upcoming 0.9 release and that’s the most important. However, the work doesn’t end and there’s many more features and performance optimization that can be added.

Then, we count on the community’s help to start collaborating with us on the GraphStore library – calling all database and performance experts. GraphStore will continue to live as an all-purpose Java graph library, released under the Apache 2.0 license and independent from Gephi (i.e. Gephi uses GraphStore but not the opposite). We hope to see it used in other projects in the near future.

graphstore-api

GraphStore API, represented as a graph

Announcing Gephi 0.9 release date

Gephi 0.9

Gephi has an amazing community of passionate users and developers. In the past few years, they have been very dedicated creating tutorials, developing new plugins or helping out on GitHub. They also have been patiently waiting for a new Gephi release! Today we’re happy to share with you that the wait will come to an end December 20th with the release of Gephi 0.9 for Windows, MacOS X and Linux.

We’re very excited about this upcoming release and developers are hard at work to deliver its roadmap before the end of 2015. This release will resolve a serie of compatibility issues as well as improve features and performance.

Our vision for Gephi remains focused on a few fundamentals, which were already outlined in our Manifesto back in 2009. Gephi should be a software for everyone, powerful yet easy to learn. In many ways, we still have the impression that we’ve only scratched the surface and want to continue to focus on making each module of Gephi better. As part of this release, we’ve undertaken one of the most difficult project we’ve worked on and completely rewrote the core of Gephi. Although not very visible for the end-user, this brings new capabilities, better performance and a level of code quality we can be proud of. This ensure a very solid foundation for the future of this software and paves the way for a future 1.0 version.

Below is an overview of the new features and improvements the 0.9 version will bring.

Java and MacOS compatibility

This release will restore Gephi’s compatibility with the latest Java versions on all platforms. This will resolve issues our users encounter with Java 7 and 8. Compatibility issues with Mac OS will also be resolved and full support for Retina display screens added.

New redeveloped core

This release will improve performance and reliability by a large margin. The graph structure at Gephi’s core has been redeveloped from scratch and will bring multiple new features, better performance and lower memory consumption. On benchmarks, simple operations such as reading nodes or setting attributes see performance improvements ranging from 2X to 100X. This new core will make many operations in Gephi faster and push the envelope even further in large graphs exploration. Reducing memory usage has also been an area of focus and we have measured a 2X reduction compared to Gephi 0.8.2 on a medium-size graph.

New Appearance module

We’re introducing a new user module named Appearance designed to combine and replace Ranking and Partition modules. Appearance will group in one place all controls acting on the node or edge appearance. The partition capabilities will also greatly improve as part of this new module and a new palette selector is being added. In addition of the default palettes, we’re also adding a cool palette generator designed to find the optimal colors (i.e. partitions can be differentiated from each other). Moreover, it will be possible to “Auto-apply” partitions as well, which is a feature that was only available for Ranking so far.

Appearance Partition Palette selector Palette Generator

Timestamp support

This 0.9 release adds a new way to represent networks over time: timestamps. So far, users could only represent time using intervals and that was cumbersome when the underlying network data was collected at fixed time intervals (e.g. one network per day). Starting with this release, Gephi will support both intervals and timestamps to represent evolving network topology and/or evolving attribute values.

GEXF 1.3 support

The GEXF format is also evolving to its 1.3 version. This version improves the support for graphs over time and introduces the ability to represent time using timestamps rather than intervals. In addition, it’s now possible to set a timestamp or an interval for the entire graph, allowing building collections of GEXF files where each represents a “slice”. This is a common request from the community and we hope this will greatly facilitate the exploration of longitudinal networks.

Multiple files import

With the 0.9 version users will be able to import multiple files in Gephi at the same time. Once the files have been read, two choices are offered, either to import each file into a separate workspace or merge them into the same workspace. The latter is a powerful option when used with dynamic graphs. Indeed, a collection of GEXF files representing the same network over time will be imported in Gephi in a single step.

Import Report Multiple Graphs

Multi-graph support

Multi-graph exampleThis release will bring support for multi-graphs, where multiple edges can exist between two nodes each with a different relationship. Users will be able to import, filter and run algorithms on these graphs but the support for visualizing these graphs will come in a further release.

New workspace selection UI

We’ve heard users’ feedback and the workspace selection user interface will be improved. The new interface will be a “tab-style” interface where each workspace is a tab and switching from one workspace to another only requires a single click. Tabs will be located at the top just under the perspective selection. The previous interface is located at the bottom right corner and will be entirely removed.Workspace Tabs

Gephi Toolkit release

A new release of the Gephi Toolkit, based on the 0.9 version will be made soon after December 20th.

Bug fixes

We’ve done a serious bug squash and already addressed many difficult issues, more to come until the release date.

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Follow us on Twitter or join the Facebook group to get the latest news. If you want to know more about this upcoming release, or want to help out please send us a note.

Improving the Gephi User Experience

This is an effort to rethink the design of Gephi authored by Donato Ricci, co-founder of Density Design and senior designer at the Sciences Po médialab in Paris, and me, creator of Gephi and an engineer at the same lab (note that I am not Mathieu Bastian, our lead developer and actual powerhouse of the project for the past 10 years).

While this text presents possible improvements and practical solutions, it does not address practical considerations of available labor. Also, be aware that this is not a formal roadmap for future releases but rather a way to open the current state of our reflections for brainstorming. So feel free to share your ideas and comments with us.

There are five main categories that structure the improvements that we currently envision:

  • Design strategy: Ensure that a coherent design philosophy is applied across the entirety of the project
  • User interface: Identify and correct user-facing errors
  • Network-focus: Re-focus design and architecture around the network’s position of primary importance
  • Filling in the Gaps: Providing expected functionality
  • Miscellany: Other minor issues

In addition, we have drafted a UI mockup illustrating some of our propositions.

Design strategy

Gephi was built by engineers without a comprehensive design strategy. This situation is fairly common: engineers approach design in an ad-hoc fashion learning by trial and errors and through casual user observation but without a formal user-testing protocol. Should the tool succeed, it is mostly because the utility triumphs over the pain of use. Gephi is an embodiment of this phenomenon in its current state. Some computer scientists may find it simple, partly because using terrible interfaces is a part of their job, but for many users Gephi is confusing. Geeks of a masochistic tendency may love the tool as a result of digital Stockholm Syndrome, but the bulk of users that could benefit from Gephi find it to be confusing and opaque. In our defense, developing desktop applications is heavily constrained and the Java technology was not helping us to overcome this difficulty. What could a designer do to alleviate this situation? Apply a strategy.

A designer does more than treating the symptoms of poor usability; he or she approaches user experience from its fundamentals. Improving Gephi requires rethinking some of its longest standing features from a new standpoint. A design strategy is the solid foundation upon which we build both a satisfying user experience and underlying software architecture.

Our design strategy fits in five basic points: obtaining substantial and organized user feedback, giving Gephi a clear workflow, implementing a facet-oriented interface layout, reordering panels from the user standpoint, and removing unnecessary features. Each point is explained in further detail along with practical guidelines for implementing potential solutions in the future.

User feedback

We cannot build a sustainable user interface without a quantitative measure of user activity. These data are necessary to support and validate design choices. One approach to obtain this information is to log and collect feedback about interface usage.

An optional logger could be implemented in Gephi to allow users to opt-in to the collection of logs in order to improve the software. Data harvesting can be done as a campaign: for example, we may ask some users to activate it for one month to evaluate the usage of a new interface paradigm that we are testing.

A clear workflow

Users need a clear and visible path to start with Gephi, in particular when opening a new file. We need to remove information to allow users focusing on what is important.

Gephi involves not only the software itself, but also the installer, website and documentation. Our ultimate goal is to make the entry process as simple as possible by coordinating these different elements. We begin by focusing here on just the software itself. We propose to consider that there are only two proper ways to enter in Gephi:

  • Opening a file (constructing a network from a pre-generated file)
  • Connecting to a data source (embedded scraper or API connection)

We also need to clarify the roles of the “open” and “import” functions. We have to clarify that:

  • If the user has a file and needs to see it in Gephi, then “Open” is the right answer
  • If the user has an external data source he or she wishes to connect to, there is distinct menu option for this function

Use case: we have observed that some users try to get in Gephi with a table of nodes and a table of links, and do not succeed in finding the right path. The problem there is that it is not explicit that it is necessary to create an empty document, go to the data table, and then import the tables. Since the pattern is “I have files and I want to see them in Gephi”, then the answer should be under the “Open” menu item.

Facet-oriented interface layout

Rethinking overall design has the virtue of allowing for the reorganization of the interface from a user-centric perspective. The current interface relies on the panels system provided by the Netbeans Platform, which provides some beneficial properties for design. We were inspired by Ben Shneiderman’s motto of “overview first, zoom and filter, then details-on-demand” and it has been quite successful. However the different views are not articulated in a coherent way and the features sometimes struggle to find the right place in terms of visibility.

We propose three simple guidelines for a better organization of the panels:

  • The global hierarchy of containers should reflect the generality of the features
  • Some panels are not facet-dependent: they should not change with the facet
  • The network should occupy a single place whatever its facet, since it is always the same object

Panels guidelines

These guidelines have two consequences. First: facet-dependent panels should be contained inside facet-independent panels; which is to say that there is a single container for all facet-dependent features. Second: the facet selector (currently the three tabs on top) has to be inside this container.

We illustrate this with a comparison between a representation of the current layout and a new simplified structure.

Web

Reordering panels from the user standpoint

A part of our design strategy is to reduce visual clutter by grouping panels that are not used simultaneously. Though it is not intuitive, we prioritize separating panels that work well together over grouping similar features. For instance the following panels should be placed in different groups in order to be used combined:

  • Filters + Layout
  • Filters + Partition or Ranking
  • Timeline + almost anything else

With the current panels there are at least three obvious groups: one with filters, another with layout, and the third with the timeline. Generic contextual information is a fourth possible group, but could be placed in a non-intrusive location like the footer. Some panels, like statistics, could theoretically be at home in any group or even as a separate window that could be invoked from a menu.

Collapsing panels concept

Panels and groups of panels create two levels, so the “window” menu should have two levels too.

Removing unnecessary features

Reducing complexity can also be accomplished by removing features. We have detected at least one clear candidate for removal, but we may find more unnecessary complications to remove.

The “preview” panel of Gephi has been increasingly simplified over iterative updates. The goal of this feature is to provide a quick way to export cartographies. Users with competence in design tend to rely on third-party tools that provide finer-grained control over the visualization, like Illustrator and Scriptographer. Thus, the focus in Gephi is to provide a quick way to export images that can be manipulated in other tools.

We propose to further streamline preview functionality by removing some advanced label features: they infrequently used, complicated, and at times internally inconsistent with other preview settings. Furthermore, it is not necessary to facilitate changes to features like label and node size and color when such adjustments can be made much more easily using other tools.

User Interface

Donato Ricci has identified various flaws in the Gephi UI. Fixing them is a priority for the future.

User-centric features: reordering workflow

Users think in terms of results they want to obtain. They have an action in mind and they search how to do it. By displaying features according to their result, we can both improve user orientation and reduce the tool’s learning curve. A few examples of follow.

We propose to aggregate Partition and Ranking under the more accessible term “Appearance”, and to reverse the order of what is asked to the user. The current interface is organized in the following way: if the user has metadata that can rank the nodes then the user can visualize it using different attributes like color and size. The new interface inverts this approach: if the user wants to color nodes then he or she chooses which metadata to use. The panel may progress like a wizard to reduce cognitive load by drawing attention only to information that is necessary for a given step.

Unified panel appearance

Collapsing advanced layout settings

The current design of Gephi does not respect the general principle of drawing attention to information that is commonly used while obscuring information that is infrequently used.

Tools of the Overview: many problems to fix

The small tool buttons on the left side of the overview panel have a number of problems including:

  • Confusing icons that do not easily communicate the use of tools
  • Indistinct icons that do not sufficiently distinguish between different tools
  • Missing tools that are commonly expected

These issues are compounded by evidence that the tools themselves do not provide sufficient utility for common use.

We propose to alleviate some of these shortcomings by putting most of these tools in a collapsed panel and to have a normal panel dedicated to the settings of each tool. We also propose to implement a default tool cursor that draws on common mouse usage paradigms to provide intuitive functionality to users:

  • A click-drag starting on the background (or an edge) of the view makes a rectangle selection
  • A click-drag starting on a node moves this node
  • A click on a node selects the node, the shift key is used for multiple selection
  • A click on the background deselects
  • A set of meta-keys changes the click function, for instance the spacebar to switch to the view-panning tool (i.e. the hand in Photoshop)
  • The secondary-click works the same

Fixing highlight colors

Highlighting works by tweaking colors so that some nodes get more contrast than others. The contrast should depend on the background color, but this is not current implementation. At the very leastthe following should be done:

  • White background: highlighted nodes darker and other nodes lighter
  • Black background: highlighted nodes lighter and other nodes darker

Network-focus

As a network analysis tool, the network itself plays an obvious central role in Gephi. We have explored different ways to incorporate the network into the software’s presentation and have developed some suggestions for modifications that would increase interface coherency.

A different layout for the panels: network as background

In this approach, the network is contained by a “background sheet” and floating panels support functions. Such a philosophy has been successfully implemented in other systems like Photoshop or Google Maps. Using the root panel for the network, like grouping facet-dependent panels, fosters the feeling that we always deal with the same object, the network. This operates on the metaphor that we are always manipulating a primary canvas that consists of the network to be analyzed.

Network as background

Statistics as an invoked panel or window

Statistics tend to be used on demand, and thus do not need to be displayed permanently. Rather, a discrete menu or button could invoke the statistics panel when needed. Removing this visual information leaves more room to focus on what is important, i.e. the network.

Workspaces: more visible, on top

The workspaces need more attention. We propose to show them as tabs on the top of Gephi. It is more natural to have the workspaces above the facet selector in the hierarchy of panels. This is consistent with the prevalence of the “tab” paradigm in the browser space.

Workspaces-on-top

Filling in the Gaps: Providing Expected Functionality

In addition to the different aspects listed above, users need some well-known common features such as an “undo” function, even if they are complex to implement.

History and undo: feasible if limited to network structure

A visible trace of previous steps, like a proverbial breadcrumb trail, provides users with a sense of orientation and confidence when exploring and manipulating data in a speculative fashion. This also accelerates the learning process by alleviating cognitive load by not forcing users to have to remember a series of unfamiliar steps. This works in tandem with an “undo” feature, which facilitates experimentation without fear of permanently corrupting data.

History and Undo are complex to implement and burden the development of plugins and modules as these functions tend to be deeply embedded in a piece of software’s architecture. This partly explains why they are not currently available in Gephi. However a prudent approach in Gephi would be to focus recording and reversal of changes to the structure of the network: Nodes and edges, their attributes (including color, size and coordinates), but not the state of panels such as filters, statistics…

An initial approach would be to cover only a minimal set of modifications of the network structure. The history would then contain information about the type of the modification, but not its exact content nor the way it was done (manually, filter, data table…). For instance:

  • Modifying attribute X for node N / n nodes / all nodes
  • Modifying color / size / position for node N / n nodes / all nodes
  • Adding / removing: node N / n nodes / all nodes
  • Adding / removing: node attribute X / n attributes / all attributes
  • …and the same for links

The history would not include operations such as exporting files, taking screenshots, modification of views, changes to settings, or other changes that did not directly affect the structure of the network

Protecting irreversible operations

Some operations are irreversible: removing nodes, edges and attributes (and possibly more). Because these operations are definitive and may cause the loss of a certain quantity of work, they should be protected. A classical solution is to ask confirmation for any definitive operation. This is a simple guideline but the result is quite user hostile. We propose a better solution, as implemented in Photoshop: when an irreversible operation has been done, when the user tries to save the network the “Save as…” window appears instead and proposes a different name (with a suffix number or “Copy of X”).

Miscellany

A few additional points deserve to be listed, and are done so in no particular order.

Manual versioning

A basic versioning feature would be appreciated: just the opportunity to save with incrementing / adding a number suffix:

  • “My Network.gexf” is saved as “My Network 01.gexf”
  • “My Network 11.gexf” is saved as “My Network 12.gexf”

A common shortcut for this is Ctrl+Alt+S.

Generalizing zoom options (more internal consistency)

We can currently set how the zoom impacts text labels. The same feature would be useful for edges, for instance to keep 1 pixel lines whatever the zoom, as well as for nodes, for instance to keep small points whatever the zoom.

Generalized zoom options

Size nodes according to area

Our eyes perceive areas. Setting a ranking to the diameter of nodes is less intuitive than to apply it to the area of nodes. We propose to offer an option to customize ranking by either diameter or area, but set the default to area.

Removing unnecessary settings about labels

Node labels and edge labels should help the user identifying nodes. However, using the color or size of labels to visualize attributes is confusing. Gephi presently contains settings to manipulate labels in this way, these settings should be removed and replaced with a simpler interface.

UI Mockup sample (work in progress)

We present here a possible approach to integrate some of the different suggestions made in this document. Consider the following image as a way to help imagine the future of the Gephi user experience.

MockupA-01

As we stated earlier, the purpose of this document is to open up the floor to brainstorming ideas about improving the Gephi UX. Please share your ideas in the comments!

PS: Thanks to Niranjan Sivakumar for his excellent proof-reading 🙂

Gephi is asleep and up to awaken

gephi round graph

Gephi has been almost inactive since quite a long time: we did not release, we did not fix issues, we did not post on the blog. This lack of recent updates creates an increasing amount of difficulties, including installing Gephi on a recent Mac computer. A lot of users ask if the project is still alive. We understand why you wonder and decided to write this post to explain where we’re at and provide to the community a preview of what’s next in Gephi’s lifecycle.

In short, Gephi is still alive yet asleep, but its reawakening is in sight. However, a series of issues prevents us from doing better right now.

The ambitious yet incomplete 0.9 release

The next planned release is Gephi 0.9 and promises to be a major release with a complete rewrite of Gephi’s core module. Performance, and especially memory usage for large graphs has been a lingering issue since the first version of the software. As explained in this article written by Mathieu Bastian – Gephi’s lead developer – the solution resides in a more efficient graph structure implementation that we named “GraphStore”. This technology brings many new features and significantly reduces the memory usage but is a large development effort and requires all modules to be adapted. Indeed, the module which stores and manages the graph is pretty much used by every other module (e.g layout, filters, preview etc.).

This work on the core graph module was initiated as part of a larger vision focused towards a 1.0 release, which aims to address a much larger set of problems, missing measures and bugs. As you may know, the current version has a various set of problems. Some issues are preventing the normal use of the software, like the difficulties to install it on a recent Mac OS X (Yosemite and Maverick). Others are incomplete or missing features, such as various user interface design issues or the improper management of categories’ colors. Finally, some internal problems are hidden in the code but nevertheless real. For example, the technology used to code the user interface (Swing) has been replaced by a more modern technology named JavaFX. For the most part, these problems require a deep rework of the code. The good news is that the most difficult part in this 1.0 vision is probably the rewriting of Gephi’s core graph module, which is what the 0.9 version focus on already.

The current 0.9 developments have reached around 80% completion and many modules, but not all, have already been adapted to GraphStore. A stable version can’t be released until this reaches 100% and all the modules are converted to the new core implementation. Other important issues such as installation issues on recent Macs have already been addressed in this development version. Finally, a series of bugs will be fixed along with minor features and improvements. Finishing the last modules and releasing the 0.9 version is our current priority.

Limited resources

Like many other open source projects, Gephi’s development is for the most part unpaid and remains an activity on the side for all contributors. The notable exception is the Google Summer of Code, which sponsored students multiple years in a row to work on the project. Therefore, the project’s progress depends on the contributors’ professional and personal situations. Although individuals are ready and willing, time is limited and there was just not enough of it lately to make significant progress. Mathieu Bastian is Gephi’s architect and has been behind the software’s key iterations since 2007. This time again he holds the keys to its future and has been involved in the GraphStore project. This complex project requires all of his knowledge of Gephi’s code and is hardly a task someone else could do at this point. Therefore, a part of our development depends on his free time, and we accept it. This situation is temporary though. Indeed, Mathieu will eventually obtain more time to conclude the work on the 0.9 release and Gephi’s development will be less dependent on him in the future.

In addition, we are working on stabilizing some resources in the long run, but our strategy requires a readjustment. Gephi needs time and energy from good java developers, clear-minded designers, and seasoned software architects. We have to entice skilled people, support their involvement and get the best from their contributions. We aim to improve the management of our limited workforce to make the development more attractive and dynamic. This evolution is organized by our team but benefits from external support. For instance, the Sciences Po médialab, the institution I belong to, provides resources for organizing the project, rethinking the user interface and some coding. These changes may not be immediately visible but we’re committed for the medium and long term.

What is next

Releasing the Gephi 0.9 version is the immediate next step. This version will include compatibility fixes and the whole new core based on GraphStore. Then, an important project to rework the overall user experience will be kicked off. It requires a technology switch (from Swing to JavaFX) and the overhaul of a majority of the modules but aims to make Gephi simpler and more intuitive to use. We already have a good diagnostic of the user experience issues in Gephi but need to explore different designs. In an upcoming blog post, I will explain our thought process on this topic with the help of Professore Donato Ricci, senior interaction designer. Eventually, the 1.0 version will be worked on and released.

Gephi is almost 10 years old. It is usable but still plagued with many well-known issues. Though sometimes frustrating, it allows users to do incredible things. We think Gephi is still relevant to research, journalism, civil society and more. We are going to give it the renewal it deserves.

Mathieu Jacomy

Google Summer of Code 2013

It’s a great news, Gephi has been accepted again for the Google Summer of Code for the 5th year! The program is the best way for students around the world to start contributing to an open-source project. Since 2009, each edition is a great success and dramatically boosted Gephi’s project development.

What is Gephi?

Networks are everywhere: email systems, financial transaction systems and gene-protein interaction networks are just a few examples. Gephi began as a university student project four years ago and has quickly become an open source software leader in the visualization and analysis of large networks. It is an important contribution to the ecosystem of tools used by researchers and big data analysts to explore and extract value from the deluge of relational data and disseminate a better understanding for people to think about a “connected” world.

Gephi is a “Photoshop” for graphs: designed to make data navigation and manipulation easy, it covers the entire process from data importing to aesthetics refinements and communication. Users interact with the visualization and manipulate structures, shapes and colors to reveal the properties of complex and messy data. The goal is to help data analysts make hypotheses and intuitively discover patterns or errors in large data collections.

Gephi’s project aims at providing the perfect tool to visualize and analyze networks. We focus on usability, performance and modularity:

  • Usability: Easy to install, an UI without scripts and real-time manipulation.
  • Performance: Visualization engine and data structures are built scalable. Supporting always-larger graphs is an endless challenge!
  • Modularity: Extensible software architecture, built on top of Netbeans Platform. Add plug-ins with ease.

Learn more about Gephi, watch Introducing Gephi 0.7, download and try it by following Quick Start Tutorial.

Gephi’s project is young, the growing community is composed of engineers and scientists involved in network science, datavis and complex networks.

List of ideas

List of ideas are availabe on our wiki. They cover various skills and level of difficulties:

* Completing Legend moduleComplete the Legend module, which was started in last year GSoC.
* GraphStore benchmark and tuningOptimize and tune GraphStore based on a serie of new well-defined benchmarks.

Please also propose your ideas on the forum. They will be considered and discussed by the community. Have a look at our long-term Roadmap.

Students, join the network

Students, apply now for Gephi proposals. Join us on the forum and fill in the questionnaire. Be careful, deadline for submitting proposals is May 3 (timeline)!

Hélder Suzuki, student for Gephi in 2009 and now software engineer at Google, wrote:
At Gephi students will have the opportunity to produce high impact work on a rapidly growing area and be noted for it.

View our previous Google Summer of Code projects here and read former students interviews.

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