How to link nodes in a mind map

Why a tree cannot hold every relation

A mind map in Canvasola is one homogeneous node tree. Every node has a label, a color, children, a position, an expanded state and a set of optional extras. That structure is good at saying what belongs to what. It cannot say that a cause in one branch produces an effect in a different branch.

Real topics have relations that cross the tree. A risk in one branch is caused by a decision in another. A step in a process happens after a step that is not next to it. Two themes you planned separately turn out to contradict each other. In a tree, all three facts go into a note, where nobody sees them.

A cross link draws the missing relation directly on the map, as a tube between the two nodes. The tree still holds the content and the link holds the connection. A concept map is built for non-hierarchical relations, but for a map you already have, a link is cheaper.

• The tree holds what belongs to what
• Links hold what belongs with what
• Relations that cross branches need somewhere to live
• Without links they end up buried in notes

Draw a link between two nodes

A cross link can be drawn between any two nodes, not only a parent and a child, and the nodes can be anywhere in the map. Start the link on one node and finish it on the other, and Canvasola draws it as a tube between them. The link is a separate object, so it never changes what a node belongs to.

One thing to know before you start: there is no link-label editor. A link is a line, not a sentence, and it carries no text of its own. So the meaning of a link has to come from somewhere else, and the usual answer is the node you attach it to.

That constraint is why links stay readable when there are many of them. If every link could carry a sentence, a map with fifty relationships would turn into a wall of tiny type. Draw the tube and let the labels at each end do the describing. The color guide shows how to make the two ends of a link findable at a glance.

• A link can join any two nodes, in any part of the map
• The link is drawn as a tube over the tree
• There is no link-label editor, so the meaning sits on the nodes
• Keep the number of links small enough to trace by eye

Note: Links are relationships, not structure. If a link connects a parent to its own child, the tree already says that, and the tube is adding nothing.

Use links for cause, sequence and contrast

Give every link one job, and pick the job from a short list. Cause links join a decision to its effect. Sequence links join a step to the step after it, even in different branches. Contrast links join two positions that disagree. Three kinds of link cover most of what a map needs.

Because a link carries no label, the two ends of the tube have to agree about the relationship. A cause link reads properly when the source node names the cause and the target node names the effect. If the source says "Pricing tiers" and the target says "Churn", the tube asserts something the reader has to work out.

A useful test is to cover the tubes and read the nodes. If the map still makes sense, the links add a layer of insight. If it only makes sense with the tubes visible, the labels need more work, because the links have become the real content.

• Cause, sequence and contrast cover most real relationships
• Name the cause at one end and the effect at the other
• If the map only works with the tubes showing, fix the labels
• Fewer links that get read beat many links that get ignored

Read the map as a set of tubes

Tubes are not arrows, and that is worth remembering. Canvasola draws a cross link as a link tube, a curved connection between two nodes, and it carries no direction marker of its own. The direction of a relationship therefore has to come from the words on the nodes, not from the shape of the line.

A map with a few tubes reads cleanly, because the eye treats them as a layer over the tree. A map with tubes everywhere stops reading as a map: crossings multiply, the branches behind them get harder to follow, and the color you assigned to each branch stops being visible.

Set a budget before you start linking. Ten links on a map of forty nodes is a strong signal, and a hundred is a drawing. When you pass the budget, the relationships are usually better handled by a note or by restructuring the tree, and the branching rules guide is where to work that out.

• A tube shows a connection, not a direction
• Direction has to come from the words on the nodes
• Ten links on a forty-node map reads well, a hundred does not
• If you are over budget, check whether it should be a branch

Follow a link that jumps branches

A link that jumps from one branch to another is the hardest to read, because you have to find the far end by eye. The fix is to make both ends visually distinct. A different node color on one end, a node icon on the other, or a collapse that folds the journey in between all help.

The 3D layer stack handles the same problem differently. Press 3 to open the stack, where each layer sits on its own depth plane, and press T to turn on trace mode and follow the links that cross between layers. The shortcut cheat sheet lists the 3D keys, and the 3D layer stack guide covers the camera presets.

Trace mode earns its place when your map is split across layers and a link runs from one plane to another. It needs WebGL, so on a machine without hardware acceleration the stack will not open and you are left reading the tubes in the flat 2D view.

• Make both ends of a long link visually distinct
• A node icon on one end is often enough
• 3 opens the 3D stack and T turns on trace mode
• The 3D view needs WebGL to run

Check the links before you export

Before you export a map with links, zoom out and look at the whole thing. You are checking for two things: tubes that run through unrelated branches and create a crossing nobody can follow, and links that point at a node which no longer says what it used to.

Links survive export. Canvasola exports a mind map to SVG, PNG, Markdown, OPML 2.0 and a plain-text outline, and the same split applies to all of them: a picture export keeps the tubes on the page, while a text export gives you the structure as an outline. Check the picture, because that is the one people will look at.

Canvasola allows up to 4,000 cross links in one map, so the limit will never stop you. The discipline comes from you: decide which links carry meaning, leave the rest out, and let the map be read as a tree first. The image export guide covers getting the final picture out.

• Zoom out and check for tubes that cross unrelated branches
• Picture exports keep the tubes, text exports keep the structure
• Up to 4,000 cross links are allowed per map
• The map should read as a tree before you read it as a network

A checklist you can reuse

• Each link has one job: cause, sequence or contrast
• The two ends of a link name the source and the target of the relationship
• Long links have visually distinct ends, using color or a node icon
• The number of links stays within a budget you set before you started
• Trace mode was used to check links that cross between layers
• The whole map was zoomed out and read once before it was exported

Common mistakes to avoid

• Linking a parent to its own child. The tree already states that relationship, and the tube adds nothing but clutter. Draw a link only where the hierarchy does not already say it.
• Expecting a label on the link. Canvasola has no link-label editor, so a tube carries no text. Put the meaning on the nodes at each end, where the reader will actually look for it.
• Drawing more than a reader can follow. Tubes multiply crossings and hide the branches behind them. A map with a hundred links stops reading as a map, no matter how good the underlying structure is.
• Exporting without a full-map check. A link that crosses three branches looks fine in the editor and obvious in a picture export. Zoom out, read the whole map, and only then export.

Frequently asked questions

Can I label a cross link to say what it means?

No. There is no link-label editor, so a link carries no text. The convention is to put the meaning on the nodes themselves, with the source naming the cause and the target naming the effect, and let the tube show the connection.

How many cross links can one mind map hold?

Up to 4,000 cross links per map. That ceiling will not be your limiting factor, because readability is: a map with roughly ten links on forty nodes is already at the edge of what a reader can trace by eye. The limit is your attention, not the app.

What does trace mode show?

Trace mode is part of the 3D layer stack. Press 3 to open the stack and T to turn on trace, which highlights the links that cross between layers, since those are invisible in the flat 2D view. It needs WebGL, so it is unavailable without hardware acceleration.

This guide is part of the mind mapping guides collection. For the wider product tour, read the complete Canvasola guide, and keep the keyboard shortcut cheat sheet open while you work.