Networks

When you are in the Networks module, which you will be automatically placed in upon login if the module is enabled for you, you will see a list of all your networks, including those networks that are owned by other users but which you have been granted access to (if any). By default, your networks will be sorted by the date that they were last modified with the most recently modified networks appearing first. You can change the way that the networks are sorted by clicking on the Sort By input and changing it to Name instead of Last Modified if you would prefer to sort your networks by name.

Uploading Networks

On the page with a list of your networks you will see a button towards the top right labeled "New Network". To upload a network you can click on this button .

A dialogue will open on the right-hand side with a number of inputs:

Network Name: Enter the name of the network you are uploading here. This name will allow you to distinguish this network from your other networks.
File Type: Select the type of file that you plan to upload. Polinode accepts three different file types - Excel, GEXF and JSON. Excel is the most common file format and is selected by default. We provide some further explanation of how to format your data in Excel below. GEXF is a specialized XML-type file-format that is sometimes used to store network data. It allows you to easily import network data from other specialized packages. JSON is a Polinode specific format that is mainly used if you want to interface with our API. However, you can upload JSON as a flat file in the same format here. You can learn more about our API and the format of JSON that it accepts here.
File: Click the Choose File button and then select the file that you would like to upload. You will also see a "Download template" button here - a template is available for each of the three file types - Excel, GEXF and JSON - and this button will change depending on what file type you have selected. Click this button in order to see a simple example of the format you have selected.
Access: When you upload a network to Polinode you can choose whether this network is a Public or Private network. Public networks can be accessed by anyone, whereas for private networks you determine exactly who can access your network (if anyone). So, if you would like others to be able to easily access your network via a URL and don't mind the data being publicly available you may want to select "Public". But if your data is private and you want to control access to your network then you will want to select "Private".
Directed: Most of the networks that we deal with in the context of Organizational Network Analysis are directed networks, i.e. the order of the relationship has meaning such that if person A is connected to person B it does not necessarilly imply that person B is connected to person A. This is why you will see that the Directed input is set to true by default. However, sometimes you may be uploading an undirected network and, in that case, you can indicate that the network is undirected by toggling this input off. A helpful example is the difference between relationships in Twitter versus Facebook. In Twitter, you can follow another user but that user doesn't necessarily follow you. That is an example of a directed network. In Facebook though if you are friends with another user then that user is also friends with you - that is an example of an undirected network.
Optional Description: If you would like to enter a description for your network, you should first toggle on the "Optional Description and Image" input. You will then see a text input where you can input a description for your network. This can include rich text such as bold, numbered lists and so on. If you enter a description for your network it will be visible to yourself and others whenever you open that network in the explore view and it will also be visible to others if the network is a public network in the list of public networks to be found under Discover.
Optional Image: Again, if you would ike to upload an image for your network, you should first toggle on the "Optional Description and Image" input. You will then have the ability to upload an optional image to associate with your network. This image will be visible in the list of network cards (i.e. the initials of the network name will be replaced by the image) and it will also be visible in the "preview" of the network if you share a public network on social media or similar.

ENTERPRISE USERS

By default all Partner and Enterprise users do not have the ability to upload Public networks for privacy and security reasons. This setting can be changed by an Admin user for the Organization under Organization Settings.

If you click on "Download template" and open that file up in Excel you will see a simple example Excel file that contains illustrative data in the Excel format that Polinode accepts. Let's take a look at this file in a bit of detail. You will see that there are two worksheets in the file - Nodes and Edges. The Nodes worksheet contains one compulsory column - Name. This column contains the names of the nodes in your network and each name must be unique as it also serves as the unique id of the node.

Next to the "Name" column you will see two example attribute columns - "Example Categorical Attribute Name" and "Example Numerical Attribute Name". These columns are in the template just to provide an example of uploading node attributes. Attribute columns are optional - you don't have to include any attributes. But you can think of attributes as being like metadata on the nodes. For example, if your nodes represent people you can include demographic attributes such as Gender, Age, Salary, etc. Attributes can be either text (i.e. categorical attributes) or numbers (i.e. numerical attributes) and you don't need to worry about letting Polinode know what type of your data is - it will work it out automatically. Also, the names of the attributes in the network are determined by the column heading in this file. So, if you are using this template file you will want to rename the column headings. For example, use say "Age" instead of "Example Numerical Attribute Name".

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The order of the columns in the Excel file does not matter. For example, "Name" does not need to be the first column. Generally though it's preferable for "Name" to be the first column.

Generally speaking you can name your attributes anything at all. However, there are a few reserved column names that have a special interpretation in Polinode and so you should only use them for their intended purpose. The first of these is "Name", which we have already mentioned above. The other is detailed below and also covered in the comment you will find in cell B1 of the template Excel file:

Imageurl: If you would like to include an image within a node, you can add a url to that image by using this reserved attribute. Many popular services for images such as LinkedIn and Twitter will work, i.e. you can enter the URL directly such as https://pbs.twimg.com/profile_images/503093797194973184/16HP_Omb.jpeg (opens new window).

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All reserved column names are case insensitive. For example, it doesn't matter whether you use "Name" or "name" or "imageurl" or "imageURL".

If you add an attribute that is not a reserved column name (e.g. Gender), you can optionally add one of two prefixes in front of that attribute name:

Any attribute names (i.e. column headings) that are prefaced with an asterix ("*") will be uploaded but interpreted as a categorical (i.e. text) attribute regardless of whether the data is numerical or not. For example, you may upload a column "*Year" and the years in that column will be processed as text rather than numbers.
Any attribute names (i.e. column headings) that are prefaced with a hash ("!") will be uploaded but not included as attributes that you can size by, color by, filter by. This is most useful when you have a text attribute that takes on many different values - including a hash in front of such an attribute significantly reduces the time it takes for the network to load each time it is accessed.

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If you have a large network (thousands of nodes say) with many attributes one way that you can decrease the load time of that network is to prepend a "!" in front of the names of categorical attributes that take a large number of different values or where there is a unique value for each node. Each time this network is opened this attribute will no longer be parsed and all the unique values enumerated. The attribute values will still be available in the right-hand side menu though on hovering over or clicking a node.

Another helpful prefix to be aware of is the hash character ("#"). Any attribute values (as opposed to column headings) that contain a hash will be treated as distinct values that you can filter by. For example, you can have a column heading Skills and one row may contain the entry “#marketing #accounting” and another row may contain “#marketing #analytics”. Polinode will parse out and treat marketing, accounting and analytics as separate values.

The second worksheet that you will see in the Excel template file is the Edges worksheet. In the Edges worksheet there are two compulsory columns - Source and Target. The Source column specifies the origin of an edge (i.e. which node it starts at) whereas the Target column indicates which node that edge goes to (i.e. the node it terminates at).

NOTE

You will receive an error message if you specify a value in the Source or Target column that is not present in the Name column in the Nodes worksheet. Using the MATCH() function in Excel can quickly tell you which values for those columns are not present in the Name column.

Just as for the Nodes worksheet, you can also specify as many attributes as you need for each edge in the worksheet. You will find that the template Excel file contains two example attributes for edges - "Example Categorical Attribute Name" and "Example Numerical Attribute Name" which you can rename as needed and add additional columns as required.

The same prefixes that are available for node attributes can also be used for edge attributes, i.e. you can use any of "!", "*" or "#" with the same result as detailed above for nodes.

The final step in creating a new network is to click the Create button at the bottom right of the window. Once clicked, your data will be checked and, if valid, uploaded. The upload can take anywhere from a few seconds for a small network through to a few minutes for a large, complicated network.

Interacting with a Network

To start interacting with a network simply click the "Open Network" button that appears when you hover over the card for that network. You will then be taken to the explore view for that network. If no default view has been specified for a network the force directed layout algorithm will automatically start running when the network is opened.

NOTE

The force directed layout algorithm is a continuous algorithm that reaches an equilibrium after it has been run for a while. On first opening a network it is just run for 5 seconds initially. This is generally not long enough for it to reach an equilibrium. In most cases you should navigate to layouts and continue to run the force directed layout until the nodes come close to stopping (i.e. reach an equilibrium) and then press the stop button under layout.

You can interact with your network in all the ways that you would expect. For example, if you left click on a node you can move it around. You can also use the scroll wheel on your mouse to zoom in and out and if you left click on the background (i.e. anywhere that is not over a node) you can move the network itself around. Furthermore, if you hover over a node the window on the right-hand-side of the screen will display all the attributes for that node. And if you left click a node that node as well as all the nodes it is connected to will be selected and the attributes for that node will be displayed in the right-hand-side window. To quickly clear such a selection you can either right-click anywhere on the background of the network or you can click on the cross towards the top of the right-hand-side window.

Network Descriptions

If there is a description for the network that you are exploring then that description will appear in the right-hand-side window when you first open the explore view. By default networks do not have a description so nothing will show but a description can be set using the "Optional Description and Image" toggle when first creating a network or when editing a network. The description can also be hidden by clicking on the cross towards the top of the right-hand-side window. Once the description has been hidden, you can show it again by clicking on the information icon towards the top of the right-hand-side window.

Searching for Nodes

At the top of the right-hand-side window you will find a search input where you can start typing the name of a node and select from the auto-completed options shown. You are able to search nodes by their name.

Selecting a node via the search input works in exactly the same way as selecting a node by left-clicking on it, i.e. that node and all of the nodes that it is connected to will be selected. It is also possible to cumulatively add nodes to the selection by using the search and select input. For example, if you select Node A, then you can add Node B and all of Node B's neighbors to the selection by typing Node B's name into the search box and selecting it. This works the same as holding down the control (or command key for Apple devices) key while left clicking nodes but has the advantage of being able to progressively search for nodes to add by their name or another attribute.

Network Layouts

We will now turn our attention to the left-hand-side menu in the explore view and step through what each of the icons in this menu does and how to use it.

The first icon in the left-hand-side menu is Layout. Clicking on this icon will open a menu at the bottom of the page. By default the force directed layout will be selected. In total there are six options for network layouts, all of which allow you to control or impact the position of nodes:

Force Directed: This layout algorithm simulates physical forces on the network. You can think of it as applying an attractive force between nodes that are connected by an edge and simultaneously applying a repulsive force between all pairs of nodes. It is a continuous algorithm that will reach an equilibrium when these forces are in balance and the nodes stop moving. It needs to be started manually by clicking the start button. Once it has been started you can stop it at any time by clicking the stop button. If it's not stopped manually it will run for the length of time (in seconds) specified in the Duration box. There are also some advanced settings that you will see for this layout algorithm. The first is the Prevent Overlap option. By default this option is set to false and you should always start running the layout algorithm with prevent overlap set to false. Once the nodes have reached equilibrium you may want to "tidy up" the layout by running the force directed layout again with Prevent Overlap set to true. The same physical forces will be simulated but in this case the relative size of nodes will be taken into account so that overlapping nodes are repelled from each other. It is significantly slower to run the algorithm with Prevent Overlap set to true which is why it should only be applied after an initial equilibrium has been reached. Gravity, Repulsive Force, Edge Weight Influence and Slow Down are all relatively advanced options that you generally shouldn't need to change. You can find out more about these options in this (opens new window) paper.
Lens: The Lens layout is very similar to the Force Directed layout in that attractive and repulsive forces are applied. However, the forces that are applied are slightly different and result in a more circular layout, i.e. a lens-like layout. This can be helpful if your network has a large number of isolates or disconnected parts of the network that you would still like to include.
Distribute Nodes: Distribute Nodes is not really a traditional layout algorithm but is generally applied when you want to add some space between nodes or reduce the overlap between nodes that have been positioned by another layout algorithm. It will iterate through all the nodes in the network and will repel nodes that are close to each other. This is different to running the Force Directed layout algorithm with No Overlap set to Yes because the latter will apply both attractive and repulsive forces whereas the Distribute Nodes algorithm will only apply a repulsive force and only between relatively close nodes. There are a number of settings available for the Distribute Nodes algorithm. The first is Margin, which is a circular Margin added around each node when determining whether a node should be repelled from each other. The second is Scale Factor, which is similar to Margin in that an area is added to each node but the difference is that the size of that area is proportionate to the size of each node whereas Margin is a fixed amount for each node. If Margin is set to 0 and Scale Factor is equal to 1 then only nodes that are actually touching will be repelled from each other. The third setting is Expansion and determines the percentage of the current space that nodes can attempt to move out ot. The final input is Speed and this determines the size of the repulsive force that is applied at each iteration.
Org Chart / Tree: The Org Chart / Tree layout will lay the network out as a tree. It is only applicable to tree networks, i.e. networks where each node has one and only one parent node. It is most often used to layout formal organizational networks (i.e. reporting lines / org charts). If you attempt to apply this layout to a network that is not a tree network then you will receive an error message. It's possible though to filter your edges first so that the visible network is a tree network before applying this layout and you can then unhide the rest of the edges.
Plot Nodes: The Plot Nodes option allows you to move from a network-type layout to a Cartesian-type layout. That is to say that you can select any attributes in your network and plot the nodes in the network by those attributes on x and y axes. This can include any attributes that have been added to the network as a result of calculating metrics (e.g. In Degree). The key inputs for this option are "Horizontal Attribute" and "Vertical Attribute". You can specify both horizontal and vertical attributes but don't need to; if you specify one only then a bar or column chart will be the result for categorical attributes. The final option is how to order categorical attributes. There are two options here - alphabetical and count. By default categorical attributes will be ordered by count. That means that they will be plotted in descending order of count, i.e. the number of nodes that fall in each category. Since the legend is always shown in alphabetical order sometimes you may wish to plot these categories alphabetically rather than by count and this is why the alphabetical option exists here.
Reposition Isolates: Often when working with network data you will find that some nodes are not connected to any other nodes (isolates) and/or that there are parts of the network that are completely disconnected from other parts of the network (connected components). It's often desirable to examine a network without these isolates or disconnected components and that is what the Reposition Isolates option allows you to do. After running a layout like the Force Directed Layout you can run Reposition Isolates and all isolates and disconnected components will be moved to the bottom of the network and arranged in a grid. The number of nodes that appear in each row under the major component of the network when you run Reposition Isolates is determined by the Number of Rows input.

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In Polinode, layout algorithms are applied to the visible network only. So, if you filter nodes and edges, you can then re-run a layout algorithm in order to run it on the visible network only. For example, only the female nodes.

The position of nodes can be reset at any time by clicking on the Reset button. This will position nodes in an equally spaced circle and you can then re-run a layout algorithm after resetting the positions of nodes.

Towards the bottom of the dropdown to select a Layout you will see that there are two additional options under the Charts sub-heading. These options are a bit different to the network layouts detailed above. Rather than being network layouts they are in fact more conventional charts that can often be very powerful when used in conjunction with the network layouts:

Collaboration Matrix: The Collaboration Matrix shows the interactions between different groups within the network. You will need to select a categorical attribute such as Division for the Row Heading and another categorical attribute for the Column Heading (which can be the same attribute as the Row Heading). After you have made these selections and clicked Start you will see a matrix summarizing the interactions between nodes with the different values of this attribute or attributes. The way to read this matrix is that the row headings relate to the source of connections and the column headings to the target (or, put alternatively, the from and to). So, each row adds up to 100% and shows how the relationships that originate from the row heading attribute are split in terms of their destination amongst the different values for the column heading attribute. Each row adds up to 100% and shows what percentage of the total visible nodes have each attribute value. You can easily export the collaboration matrix to Excel by going to Export and then changint the format to Excel. The colors assigned to the minimum value and maximum value in the collobartion matrix can be edited using the Min Color and Max Color inputs (click the Start button again after you have made a change here). There is also the option to Normalize the collaboration matrix by size. If you toggle this on, each element in the matrix will be divided by it's relative size. So, suppose, you have selected Division for both the row and column headings and Accounting to Accounting in the matrix is 6% and Accounting makes up 3% of the total visible nodes in the network, then the normalized value for this cell would be 6%/3% = 2.0x. The legend in the collaboration matrix can also be used to dynamically filter the visible cells in the matrix by dragging the min and max thumbs.
Membership Matrix: The Membership Matrix option does not look at the connections that go from one group to another group like the Collaboration Matrix but instead looks at what proportion of each group is in another group. For example, if you were to select Division as the Row Heading and Gender as the Column Heading it would show you what the gender split was for each division. The same ability to change the min and max colors as well as to use the legend to filter the matrix apply to the membership matrix.

It's also possible to add layouts as a layer to a view by clicking the Add as Layer button. We will discuss views and layers shortly. This is helpful if you want to re-run a layout each time you open a view. If the underlying data of your network is not changing though you likely won't need to do this and don't need to add layouts as layers.

Opening Views

In Polinode, it's possible to save up to 50 views per network (on the Professional Plan or above). A view in Polinode is a set of settings for the network, essentially each view preserves the following:

The position of nodes, which you can set using one or more of the layouts provided and detailed above.
The Layers for the view, which you can think of as like a set of operations to be applied and the order in which those operations are to be applied (for example size nodes by an attribute then color nodes by another attribute).
Visual settings for the view such as the background color, edge type, color of nodes, etc.

To open a saved view in Polinode you simply click the Open button in the left-hand-side menu and then click on the name of the view that you would like to open. That view will then be applied, including the positions of nodes, the saved layers and the visual settings.

Within the open views dialogue that will open you can also make any saved view the default view for the network and you can delete any previously saved view by using the icons under Actions. The default view for a network will open automatically when the network is first opened in the explore view. By default views are sorted by the date that they were last modified but you can also sort them by the name of the view or the date created by clicking those column headings in the table. You can also search for views by name using the search input.

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When a view is open for the network you will see that the Open button will turn blue. This helps you see quickly whether a view is open or not and is true not just of the open button but also most other buttons in the left-hand-side menu. For example, if a filter is active that button will be blue and if a roll-up operation has been applied then that button will be blue.

When a view is open for the network you will see the name of that view next to the name of the network towards the top left of the screen. It's possible to clear or exit a view by using the Reset View button that is visible at the bottom right of the right-hand side window when you toggle the Layers button on.

Saving Views

In order to save a view for a network, click on the Save button and a dialogue will open with two tabs. Use the first tab to save a new view for the network by specifying a name for the view that you are saving as well as whether the view should be treated as a default view or not. If the network already has a default view and you select "Yes" here then the previous view will no longer be treated as the default view and will be replaced with the new view that you are saving.

The second tab in this dialogue gives you the ability to update an existing view. If you have a view open you can use this dialogue to update that view. Whether you are saving or updating a view, once you confirm that you are ready to save the view the node positions, layers and visual settings will be preserved and can be accessed later by clicking the Open button above.

Template Views

Standard views are available at the network level, i.e. each one is associated with a specific network. However, it is possible to save and apply what are called Template Views. A template view can include a set of layers to be applied and/or a set of visual settings (such as node colors, background color, etc). It doesn't include node positions however and the reason for that is that template views are designed to be applied across networks and sit at the user level rather than against a specific network. So, you can use a Template View to for example save a particular color theme that you can apply with a single click to any network.

In order to access template views simply click on Templates in the left-hand-side menu. This will bring up a dialogue with two tabs. The first is a list of all available template views. All accounts in Polinode have two default template views available and they are Dark Theme and Light Theme. So, if you would like to apply a Light Theme rather than the default Dark Theme you can click the apply button next to the Light Theme template view. You can also delete any existing template views from this table.

The second tab in the dialogue is used to save a new template view - the only input required is a name for the template view and once saved that template view will be available for future use and will capture the layers and visual settings that you see at the time you save it.

If you would like to update an existing template view the easiest way to do so is to apply it to a blank network, make the changes and then save a new template view before deleting the old template view.

Labels

The Labels option in the left-hand-side menu gives you a lot of control over the appearance of node labels. By default, labels are only shown once you select a node and then they are only shown for that node and the nodes that it is connected to. You can change this though by changing the Show Labels setting to Always in which case labels will be shown for all visible nodes. For smaller networks this may be desirable but for most networks showing labels for all nodes will fill the screen with labels. However, you can easily reduce the number of labels that are shown though by clicking Filter and then clicking on the Labels tab before filtering labels by an attribute, for example the same attribute that you are sizing nodes by if you are sizing nodes by an attribute.

There are a total of three other settings for labels in the bottom window:

Label Background Color: You can use this input to customize the background color of the labels with this input.
Attribute: By default node names will be used for node labels, however, you can select any text attribute for nodes to use for the label text here.
Style: By default your node labels will be Bold but the style of the text can be changed to unbolded (i.e. regular).

Layers

In Polinode you can add and then preserve a series of operations that you want to apply to the network and these operations are saved as layers. You can think of layers in Polinode as being like layers in Photoshop. The important point is that the order that you are applying those operations is preserved. So, for example, you can first calculate a metric like In Degree and then size nodes by In Degree.

There are a total of 13 different types of layers in Polinode:

Running a layout
Calculating a metric (any of a node, edge or network metric)
Coloring nodes by an attribute
Coloring edges by an attribute
Coloring labels by an attribute
Sizing nodes by an attribute
Sizing edges by an attribute
Sizing labels by an attribute
Filtering nodes by an attribute
Filtering edges by an attribute
Filtering labels by an attribute
Setting the shape of nodes by an attribute
Rolling nodes up by an attribute

You will notice that all of these options with the exception of layout appear as the six options in the left-hand side menu immediately below the Layers option, i.e. they are Metrics, Color, Size, Filter, Shapes and Roll-up.

If you would like to view a summary of all the layers that are currently applied you can click on this Layers button in the left-hand side menu and a summary of the layers will then appear in the right-hand side window. You can edit any of these layers at any time by clicking on the edit button for that layer. You can also remove a layer by clicking on the delete icon for that layer. And, finally, you can toggle a layer on or off by clicking the icon that looks like an eye to the left of the layer box.

Metrics

Typically an important part of network analysis is the calculation of metrics based on the network. Polinode provides the ability to calculate 27 different node metrics with a full list available by clicking on the "Advanced Metrics" button after opening the Metrics dialogue. Each of these 27 metrics is summarized below:

Advanced Communities: This is an advanced version of the Louvain Communities algorithm (see below). The resolution parameter allows you to tune the size of the resulting communities - a resolution of 0 will place all nodes into a single community whereas of a resolution of two times the number of nodes will result in each node being assigned it's own community. The default value of 1 will apply the algorithm without regard to the size of the resulting communities. There is also an optional maximum community size parameter that, if used, will limit the resulting communities to be no larger than the inputted value. For large networks the algorithm is considerably faster with max size left blank. Read more here (opens new window).
Average Neighbor Degree: Average Neighbor Degree for a node is the average number of edges (i.e. degree) that a node's neighbors have. For directed networks, you can specify whether to use in-degree or out-degree for each of the source and target nodes in the calculation. Read more here (opens new window).
Betweenness Centrality: Betweenness Centrality for a node is the total number of shortest paths that pass through that node and, if the Normalized option is selected, divided by the total number of shortest paths in the network. It is a measure of how much a node is a 'bridge' between other nodes in the network. Read more here (opens new window). Betweenness can be computationally expensive to calculate, particularly for large networks, which is why the option to sample a subset of nodes is provided as an input. If Apply Edge Weights is set to Yes then the inverse of the edge weights will be used such that a larger edge weight effectively reduces the distance between two nodes rather than increasing it.
Binary Flag: Binary Flag is a helper metric that is equal to True for a node if for the selected attribute below is equal to one of the selected values below for that node. Otherwise, it is equal to False. It is particularly helpful when used together with the External edge metric.
Brokerage: Brokerage here refers to Gould-Fernandez brokerage. Given an attribute, there are five kinds of brokerage possible: Coordinator, Consultant, Gatekeeper, Representative and Liaison. This metric will count up and return the number of times that a node acted in each of those roles. Read more here (opens new window).
Closeness Centrality: Closeness Centrality for a node is the reciprocal of its farness. The farness of a node is the sum of its shortest path distances from all other nodes. The greater a node's Closeness Centrality relative to other nodes, the closer it is on average to other nodes in the network. Read more here (opens new window).
Clustering: The Clustering coefficient for a node is the fraction of possible triangles through that node that actually exist. The higher a node's clustering coefficient, the more embedded it is in the overall network. Read more here (opens new window).
Communities: Similar to Advanced Communities this is based on the Louvain Communities algorithm but without some of the advanced options. Louvain Communities are non-overlapping groups of relatively closely connected nodes found by an optimization algorithm. Read more here (opens new window).
Connected Components: A Connected Component is a set of nodes that are connected to each other. A directed network will be treated as an undirected network for the calculation of Connected Components. Read more here (opens new window).
Constraint: Constraint is related to the concept of structural holes and measures the extent to which a node is able to take advantage of structural holes in their network. Constraint will be higher if a node's connections are highly connected between each other, either directly or indirectly through a mutual connection. Read more here (opens new window).
Core Number: Core Number for a node is the largest value k of all k-cores containing that node where a k-core is the largest possible subgraph in the network containing nodes with a Total Degree of k or more. Core Numbers can be helpful in the decomposition of large networks. Read more here (opens new window).
Current Flow Closeness Centrality: Current Flow Closeness Centrality is similar to regular Closeness Centrality but instead of a shortest path measure for distance, effective resistance inspired by electric circuit models is used. Read more here (opens new window).
Effective Size: Effective Size is related to the concept of structural holes and the reduncancy of connections. It measures the number of people that the node is connected to but controlling for (i.e. reducing by) the redundancy of those connections. Read more here (opens new window).
Efficiency: Efficiency is equal to effective size divided by total degree. If a node has no redundant ties then the effective size will be equal to total degree and efficiency will be equal to one. Efficiency is the proportion of a node's ties that are non-redundant. Read more here (opens new window).
Eigenvector Centrality: Eigenvector Centrality is motivated by the idea that nodes connected to other nodes that are central should themselves be relatively central, i.e. being connected to a central node contributes more than being connected to a non-central node. It is not always well defined for directed networks and it's generally preferable to calculate Katz Centrality for directed networks. However, should you calculate eigenvector centrality for a directed network Polinode will return "left" eigenvector centrality (i.e. corresponding to the in-edges). Read more here (opens new window).
External vs Internal: External vs Internal (EI) calculates, for a given attribute, the percentage of a node's edges that connect to nodes that do not share the same value for that attribute (external connections) vs connections to nodes that do share the same attribute value (internal connections). If type is Total the metric will be calculated for all edges, if type is In then the metric will be calculated only for a node's incoming edges and if type is Out then only for a node's outgoing edges.
Harmonic Centrality: Harmonic Centrality for a node is the sum of the reciprocals of the shortest path distances from that node to each other node in the network. It is closely related to Closeness Centrality with the key difference being that the reciprocal is taken for each distance rather than taking the reciprocal of the sums of the distances. Read more here (opens new window).
HITS: Hyperlink-Induced Topic Search (HITS) for a node gives two metrics - Hubs and Authorities. A node has a relatively high Hubs score if it links to other nodes and a relatively high Authority score if it is linked to by other nodes. Read more here (opens new window).
Identify Influencers: Identify Influencers is a heuristic that finds the most influential nodes in the network in the sense that together the count of those nodes and the nodes connected to those nodes is maximized, i.e. coverage of the network is maximized. Read more here (opens new window). It is also possible to limit the influencers identified to certain attribute values by using the Limit by Attribute option. This is helpful if, for example, you want to identify influencers in an organization but only at the individual contributor level.
In Degree: In Degree for a node is a straightforward measure of centrality - it measures the total number of nodes linking to that node. Read more here (opens new window).
K Clique Communities: A K Clique Community is the union of all cliques of size k that can be reached through adjacent k-cliques where a k-clique is a group of k nodes that are all connected to each other and a k-clique is said to be adjacent to another k-clique if it shares k-1 nodes with it. Communities produced by this algorithm are generally not distinct and will overlap so an attribute is added for each community found. Read more here (opens new window).
Katz Centrality: Katz Centrality for a node takes into account not just the neighbors of that node but also their neighbors and so on, applying an attenuation factor of alpha so that the influence of nodes declines on every step away from the target node. Read more here (opens new window).
Load Centrality: Load Centrality for a node is the total amount of some commodity passing through that node when one unit of the commodity is sent from each node in the network to each other node in the network and the commodity is split equally at branching points and aggregated at meeting points.. Load Centrality is very similar to Betweenness Centrality and also measures 'bridging'. Read more here (opens new window).
Out Degree: Out Degree for a node is a straightforward measure of centrality - it measures the total number of nodes that that node links to. Read more here (opens new window).
Pagerank: Pagerank for a node is a ranking of relative importance in the network based on the structure of incoming edges for that node. It was originally designed to rank web pages. Similar to Katz Centrality, alpha is an attenuation factor. Pagerank for undirected networks will be calculated by transforming each undirected edge into two directed edges. Read more here (opens new window).
Rename Node Attribute: This is a helper metric that allows you to rename either a node attribute or the values of a node attribute. For the former, suppose we calculate In Degree but want to call it something different. We can use this metric to rename "In Degree" to say "Total Incoming Connections". Another example, would be where we want to rename the actual values of an attribute. Again, suppose we calculate Advanced Communities. The values will be Community 1, Community 2, etc. We can use this helper metric to rename Community 1, Community 2, etc. to more descriptive names for these identified commmunities.
Total Degree: Total Degree for a node is a straightforward measure of centrality. It is simply the total number of edges that that node has, i.e. for directed networks it is the sum of In Degree and Out Degree. Read more here (opens new window).

Some of these metrics are only available for directed networks and some are only available for undirected networks. If a metric is not available for your network you will see a message to that effect to the right of the dialogue.

There is also an option to view Basic Metrics only which are - Communities, External vs Internal, In Degree, Out Degree and Total Degree. You can toggle between the basic metrics and the full advanced metrics (which includes the basic metrics) using the toggle labelled Advanced at the bottom left of the dialogue. If you are new to network analysis you may want to focus just on the basic metrics to begin with and it's worth noting that you can generally gain a great deal of valuable insights using just these basic metrics.

To calculate a metric simply select it and then input any options (if relevant) and click on "Calculate and Add as Layer". The metric will then be calculated with the result added as an attribute (or attributes) for all nodes. Importantly the metric will only be calculated for the visible network, i.e. after any filters have been applied. This means that you can use Polinode to dynamically calculate metrics for sub-networks. For example, you could filter a network by gender to focus just on say female nodes and then, if you were to calculate In Degree the In Degree calculated will be for the female network only.

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When you add a metric it doesn't alter the underlying network data but rather a layer is added so that the metric is recalculated each time a view is opened. For larger networks some metrics can take a while to compute. If this is the case for you, you can simply export your network to Excel after calculating the metric and then reimport that Excel file to update the network. The metric will then be added as an attribute and won't need to be recalculated each time a view is opened.

The second tab in the metrics dialogue provides four advanced edge metrics (two if Basic Metrics is selected):

Edge Betweenness: Edge betweenness is a measure of the total number of shortest path in the network that pass through an edge relative to the total number of shortest paths in the network overall. Just as for Node Betweenness, you can select a number of nodes to sample as a percentage of the total nodes in the network. If Apply Edge Weights is set to Yes then the inverse of the edge weights will be used such that a larger edge weight effectively reduces the distance between two nodes rather than increasing it.
External: For a given attribute, the External metric is True for an edge if that edge connects two nodes with different values of that attribute and False if that edge connects two nodes with the same value for that attribute. For example, if the attribute selected is Gender and an edge selects two males then External will be False for that edge whereas if the edge connects a male and a female then External will be True for that attribute.
Mutual: The Mutual metric is True for an edge if a reciprocal edge also exists, i.e. for an edge from a source node to a target node the metric is true if there is also an edge from the target node to the source node.
Rename Edge Attribute: This is a helper metric that allows you to rename either an edge attribute or the values of an edge attribute. It works in the same way as Rename Node Attribute (see above).

The third tab in the metrics dialogue provides for six advanced network metrics (four if Basic metrics is selected). These network metrics are a bit different to the Node and Edge metrics in that they are a single metric for the whole network rather than having different results for each node or edge. For the less computationally intensive metrics, you will see a real-time result to the right of the dialogue. For the more computationally intense metrics (Average Path Length and Diameter) you will need to click the Calculate And Add As Layer button in order to see the value for the metric which will be visible as a bold value in the resulting layer box. Here is a summary of each of the six metrics available in this tab:

Average Path Length: The Average Shortest Path Length. The N*(N-1) shortest paths are calculated for the network (where shortest path measures the number of "hops" or "steps" between two given nodes). Those shortest paths are then summed up and divided by N*(N-1) to calculate the Average Shortest Path Length for the network. Read more here (opens new window).
Average Total Degree: The Average Total Degree is the sum of the Total Degree for all nodes divided by N. Read more here (opens new window).
Density: Network density is the number of relationships that do in fact exist as a percentage of the number of potential relationships that could exist in the network. Read more here (opens new window).
Diameter: The Diameter of a network is the longest shortest path across all pairs of nodes in the network. Diameter is calculated for the largest connected component in the network only (if applicable) and directed networks are converted to undirected networks. Nodes that cannot reach other are ignored for the average shortest path calculation. Read more here (opens new window).
Number of Nodes: The total number of visible nodes in the network.
Number of Edges: The total number of visible edges in the network.

Color

Clicking on the color option in the left-hand-side window will open a window at the bottom of the page with three options - Nodes, Edges and Labels. It is possible using these tabs to color any of nodes, edges or labels by any attribute. Nodes and labels can be colored by any node attribute and edges can be colored by any edge attribute. To select an attribute for nodes for example, simply select the name of the attribute from the "Color Nodes By" input. If this attribute is a categorical attribute then each value for the attribute will be colored a different color and you can edit these colors by either clicking on the "Edit Colors" button or the names of these attributes in the legend that will appear. Alternatively, if the attribute you select is a numerical attribute then the maximum value of the attribute will be colored one color and the minimum value of the attribute another color with those two colors interpolated for all values in between. These max and min colors can also be adjusted by clicking on either Edit Colors on the legend itself. Where the attribute is a numerical attribute a Thresholds slider will also appear. With this slider you can specify where you want the breakpoints to be for the max and min values. For example, if your minimum value is 1 and you select 3 for the minimum threshold then both the node with the value of 1 will be colored the minimum color as well as any nodes with attribute values that fall between 1 and 3.

Coloring edges and labels works in the same way as described above for coloring nodes except there are some additional options for coloring labels. By default all labels are the same color and the Color Labels Option is set to Custom Color, which you can change in this input. If you would like to color labels by an attribute instead you will need to select "Attribute" for the Color Labels Option. Edges can also be colored by either the Source or Target node color if desired.

Once you have colored nodes, edges or labels by any attribute you can add that operation as a layer by clicking the "Add as Layer" button or you can clear it by clicking the "Clear" button.

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If you click on a number that sits either above or below a slider thumb you can edit that number in order to set an exact value for it. Simply hit the enter key once you have finished editing the number.

Size

Clicking on the size option in the left-hand-side window will open a window at the bottom of the page with three options - Nodes, Edges and Labels. You can size nodes, edges or labels by any numerical attribute using the inputs here. For example, to size nodes you would click on the "Size Nodes By" input and will be presented with a list of numerical attributes for nodes. Select one of these attributes and nodes will be sized by it. You will likely also want to adjust the maximum and minimum size for nodes directly above this input. And to the right of the selected attribute you will find a Thresholds input which allows you to select the attribute value to apply the minimum size below and the maximum size above.

Once you have sized the nodes you can add the operation as a layer by clicking the "Add as Layer" button or you can reset sizing by clicking the Clear button. The approach for sizing edges and labels is exactly the same as for sizing nodes.

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If you want to apply edge weights when calculating metrics that support using edge weights you will first want to size edges by an attribute using this input and add that operation as a layer.

Filter

Filtering works in a similar way to coloring and sizing - simply click on the filter option in the left-hand-side window and a new window will open at the bottom of the page with three tabs - Nodes, Edges and Labels. Let's look at filtering nodes. The first thing that you will want to do is select an attribute to filter the nodes by using the "Filter Nodes By" input. You can filter nodes by any attribute, i.e. both categorical attributes and numerical attributes are supported. The input looks a bit different for the two types of attributes though.

If you select a numerical attribute to filter by you will see a Thresholds slider appear. A filter works in exactly the way that you would expect it to - all nodes with an attribute value less than the minimum threshold you select will be hidden and all nodes with an attribute value greater than the maximum threshold you select will be hidden.

Filters can be stacked on top of each other. So, for example, you can add a filter so that only females are shown and then you can add another filter to show only employees with a tenure of more than five years. Filters stacked together like that work like an AND operator.

If you select a categorical attribute rather than a numerical attribute, the logic above still applies but the input appears slightly differently. Rather than see a slider you will instead see a list of categorical attributes under the "Selected Attribute Values". By default all of the attribute values will be selected. You can change the attribute values that are selected by left clicking within the Selected Attribute Values. You can also quickly deselect all attribute values by toggling the Select All button at the top of the input you see once you click into the Selectted Attribute Values input.

Once you have set up your node filter, you can add it as a layer by clicking on the "Add as Layer" button or you can reset it by clicking "Clear". Edge and Label filters work in exactly the same way as node filters described above.

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When you calculate metrics in Polinode, they are calculated on the visible nodes and edges only. This means that you can apply a filter or filters prior to calculating a metric and that metric will be calculated for the sub-network only. Layouts are also dynamic to the visible network.

Shapes

By default all nodes are circles but it's possible to dynamically set the shape of nodes by any categorical node attribute. To do so simply click on Shapes in the lef-hand side menu and then select the categorical attribute that you want to use from the Set Node Shapes By input. Node shapes will then be automatically set according to the attribute values for that selected attribute (rotating between circle, triangle and square). You can change the assigned attributes by attribute value by clicking the Edit Shapes button and you can revert node shapes so that all nodes are circles again by clicking the clear button.

Roll-up

You can roll-up nodes by any categorical attribute. Simply select the categorical attribute that you would like to roll-up nodes by and all the nodes that share the same attribute value for that categorical attribute will be combined together. Nodes in the network will then represent the attribute values and the edges between those rolled-up nodes will represent the aggregated connections between nodes that share the same attribute values.

When you roll nodes up, new attributes are calculated for both nodes and edges. The new attributes that are calculated represent the Average and Total values across all numerical attributes for all nodes that share the same attribute values for the rolled-up values. For example, if you roll nodes up by Division and you have previously calculated In Degree then both Average In Degree and Total In Degree will be calculated for each division.

The position and color of rolled up nodes will be set to the average position and average color of the nodes that share the same attribute value.

Rolling up nodes can be preserved as a layer by clicking on the "Add as Layer" button and the roll-up can be cleared by either deleting the layer or clicking the Clear button.

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If you export a rolled-up network to Excel you can then re-import that network as a new network. This gives you more flexibility with respect to the rolled-up network, including giving you the ability to save node positions for the rolled-up network.

Export

There are three options for exporting networks within the explore view:

PNG: This option will allow you to export the network as a PNG image and will include the legend and background - essentially everything that you see. You can remove the legend(s) if desired under Settings and you can also set the background to a transparent color under Settings.
Excel: This option gives you the ability to export your network to Excel in exactly the same Excel format as you can import networks into Polinode. It will include all node and edge attributes, including any metrics that you have calculated. If layout is set to one of the Charts options then the exported Excel file will be the Excel data from that chart rather than the network data.
GEXF: Graph Exchange Format (or GEXF for short) is an XML-type format that is designed specifically for network data. You can export your Polinode networks to this format for import into other specialized network packages. This export includes not only the node and edge attributes but also the position and color of nodes / edges.

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You can export a network image with a transparent background color by first navigating to Settings and then to the Background tab and setting the background color alpha (the fourth number) to zero. Then, if you export to PNG, the image will have a transparent background and you can overlay it over another background in say Powerpoint or even an image of a map.

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Export to Excel and GEXF is only available for Owners of networks and for users with Edit permission for a network. Users with View permission are not able to export to these formats.

Settings

Clicking on Settings within the left-hand-side menu will display the Settings window at the bottom of the page. There are four tabs here - Edges, Legends, Selection and Background. For the most part these settings control the visual appearance of the network.

The first tab - Edges - allows you to control the visual appearance of edges in the network. There are five settings related to edges altogether:

Edge Style: Here you can select between curved edges and straight edges. Importantly, for directed networks, straight edges will overlap each other if there is an edge from both the source to the target and from the target to the source. Sometimes though you may want the more simplified view that straight edges afford.
Show Edges: Use this setting to toggle the display of edges on and off. For larger networks you may want to hide edges to make the interaction with the network faster and for some large networks we will automatically hide edges (and they can be turned back on via this setting).
Self-Loops: By default a node's connection to itself is shown as a circular loop. Quite often it's preferable to hide these self-loops and you can do so by changing this setting to No.
Arrows: By default, edges in directed networks have arrows at the target end of the edge. You can turn these arrows off by changing the toggle here.
Arrow Size: If the network is a directed network and arrows are set to show then you can increase or decrease the size of the arrows relative to the thickness of the edges using this slider.

The second tab within Settings is Legends and it is here that you can control whether each of the legends (for nodes, edges, labels and shapes) appears or not.

The third tab is Selection and in this tab you will find settings that control the visual appearance related to your interaction with the network. The first setting is Node Selection and the default is for both a node and its neighbors to be selected when you click a node. You can change this default behavior though so that only a single node is added to the selection when a node is clicked (note that you can expand the selection by holding the control key down or the command key on Macs). If Node Selection is set to Node Plus Neighbors you will see another option which is Edge Selection. The default for this option is All Edges so that when you select a node (and therefore its neighbors too) all of the edges will be displayed within that group (i.e. the incoming edges from that node to its neighbors as well as the outgoing edges and the edges between the neighbors themselves). The other options available here allow you to narrow down the nature of your selection to say just the incoming edges (and associated neighbors) or just the outgoing edges (and associated edges) or just the incoming and outgoing edges but not the edges between the neighbors themselves.

The final tab is Background and contains an input for setting the background color of the network.

The final button in the left-hand-side menu is the expand and collapse menu button. By clicking the expand button you will see a larger version of the left-hand-side menu that includes text descriptions of each item in the menu. You can then collapse that menu back down to the smaller version by clicking on the Collapse option.

Using the Legend

Whenever you color nodes, edges or labels a legend will appear or be updated in the top left of the screen. This legend will automatically update to reflect any filters that you have applied or do apply. Clicking on the labels or circles in this legend gives you a quick way of changing the colors of the nodes in the network. This is an alternative to clicking on the "Edit Colors" under Color.

Keyboard Shortcuts

There are a number of keyboard shortcuts available to you in the explore view. Some of the more advanced actions that you can do with keyboard shortcuts are not available via the menus so it's generally a good idea to familiarise yourself with the shortcuts summarised below:

Home: Rotate right
End: Rotate left
Left click node: Select node and all connected nodes
Control + left click node: Add node and all connected nodes to selection (note this is the Command key for Macs)
Right click outside nodes: Clear all selections
1: Add all neighbors to selection
g: Start / stop layout algorithm
shift Multi-select via the mouse will be activated when the shift key is held down
s: Scale the network to fit the screen

Editing a Network

We now return back to the list of networks view and walk through the other functionality that is available there. So, if you return to that list view of all of your networks you will notice that each card has a menu available when you click on the three dots. The first item in that menu is Edit.

Once you have uploaded a network, if you want to edit that network you don't need to create an entirely new network. Rather, you can use this edit button. Simply click on that button and you can update the underlying network data by selecting a file with your updated network data in it. You can also edit the network name here or change a network from Public to Private or vice versa. You can also edit whether the network is directed or not and upload or edit an image associated with the network as well as edit the description of the network here. It's worth noting that you don't need to upload a file each time you edit a network. So, if you just want to change the name of the network for example you can click Edit and change the name of the network only before clicking update.

Duplicating a Network

If you would like to clone or duplicate a network you can do so using this Duplicate menu item. Simply click Duplicate and enter a new name for the network you are about to clone and indicate whether it should be Public or Private. All of the underlying network data as well as any saved views for that network will be duplicated into a new network in your account.

Manage Users

By default only the Owner of a network has access to that network if the network is private. The Owner of a network is the user who first created that network. However, the Owner of a network can grant permission to other users to access that network. You do this by clicking on the Manage Users button. This will show you a summary of all of the users that currently have access to the network. To add a user click the Add User button and a dialogue will appear where you enter the email address of the user that you want to add. Then click Check. Polinode will check whether that user already has a Polinode account and let you know whether they do or not. After you have entered the email of the user you will want to edit the permissions that you would like to grant them. You can grant a user either Edit or View permissions. With Edit permissions they can change the underlying data, save new views, etc. With View permissions only they can just view the network but cannot edit it.

The other thing that you will need to decide is whether the user you are adding will have permission to grant other users access to the network themselves. And whether or not they will have the ability to remove the access of other users (or edit their permissions).

Once you have selected the appropriate permissions, click the Add User button and the user will receive an email informing them that they have been granted access to the network.

This Manage Users drawer for a network will only be visible to users that have the ability to add or edit users for the network.

It's also possible to add and manage users for a particular network in bulk by using the Upload Users button.

Export to Excel

The next menu item that you will see when clicking on the three dots is Export to Excel. After confirming that you do indeed want to export the network data to Excel, an Excel file will be downloaded to your computer with all of the network data and it will be in the same format as is used for the upload of network data in Polinode (please see above).

Archiving a Network

You may find that you have a large number of networks in your Polinode account after a while but only need to work on a subset of them at any one time. The ability to archive and unarchive networks is designed to allow you to do this. Simply click this menu item to archive a network. It will then no longer be displayed in the list of your networks unless you switch the Show Archived toggle to true towards the top of the screen. If a network is archived, this menu item will change to Unarchive and you can use it to unarchive your network.

Deleting a Network

The final item you will see when clicking the three dots is delete. This menu item is only active for the Owner of the network. Once clicked, you will be asked for confirmation and then the neetwork will be permanently deleted.

Actions on Multiple Networks

For convenience, some actions may be applied across multiple networks at the same time. To achieve this, hover over one of your network cards and you will see a checkbox appear towards the top left of the card. Select this checkbox to select that network. You will then be able to select other checkboxes to add other networks to the selection and you will see a dialogue appear towards the bottom of the screen. This dialogue gives you the ability to either Combine, Archive, Unarchive or Delete multiple networks at the same time. We have previously been through Archive, Unarchive and Delete in the context of individual networks. Combine though is functionality that we have not previously described. The Combine option here gives you the ability to combine multiple networks together in order to create a new network that will contain all of the nodes and all of the edges of the networks you are combining together (and where nodes with the same names / identifiers are treated as the same node in the combined network).

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