Animated Flow Lines: Show Direction of Movement on a Line

A normal line shows where something goes. An animated flow line also shows which way it moves. The pattern on the line travels along it, so a reader can see direction at a glance without reading any labels.

This is useful for maps of movement, such as supply routes, traffic flow, water and utility flow, migration paths, evacuation routes, and network diagrams.

Animated flow lines are a Pro line style. If you are on a free plan, you may have a small number of trial credits to try Pro line styles before upgrading.

Turn on animation for a line

Animation is a line style, so you set it the same way you set a solid or dashed line.

1. Select the line on your map.
2. Open the line type picker.
3. Pick one of the animated styles.

In the picker, each animated style sits next to its normal version. The left swatch is the still style and the right swatch is the animated one, so you can compare them before choosing. The animated swatches move in the picker, which shows you exactly what the line will look like.

To turn animation off again, pick the matching still style from the same list.

The animation styles

You can choose from five animated styles.

• Flow arrows. Arrows travel along the line. This is the clearest choice for showing direction.
• Dashes. The dashes march along the line.
• Zigzag. A zigzag pattern travels along the line.
• Wave. A wave pattern travels along the line.
• Dots. Dots march along the line, with no line drawn between them.

Flow arrows also work with the arrow line styles. If your line already has an arrow head, or arrows along it, the animated version keeps that look and adds movement.

Which way the pattern travels

The pattern always travels in the direction you drew the line, from the first point you clicked to the last.

If the flow runs the wrong way, reverse the line's points and the pattern will follow.

Change the speed

Each animated style has a gear button next to it in the picker. Click the gear to open the Speed menu and pick a speed.

The default speed is 1. Lower numbers are slower and higher numbers are faster. The useful range is about 0.25 to 4.

Speed is matched to your zoom level, so the line keeps a steady real-world pace as you zoom in and out. It will not appear to race off when you zoom out.

Change the arrow colour

Select the line and use the Arrow Colour control to change the moving pattern's colour and opacity. Arrow Colour is saved separately with the line, so changing the line fill or your Settings fill later does not change an existing animated line.

When you first apply animation, Scribble Maps copies the line fill into Arrow Colour. If the line has no fill set, it copies the current fill from Settings instead. This is a one-time starting value, not a live link to Settings.

Older saved animated lines may not have a separate Arrow Colour yet. The first time one is rendered, Scribble Maps uses its line fill when available, otherwise the current Settings fill, and then saves that result as its Arrow Colour. After it is saved, it does not track or follow later Settings fill changes.

In saved style data, Arrow Colour and opacity use color_3 and alpha_3; the line fill remains separate in color_2 and alpha_2.

Lines that meet

When two animated lines meet, Scribble Maps keeps the flow reading as one path.

• If one line ends partway along another line, its arrows turn onto the second line and keep going. This looks like a stream joining a river.
• If two lines share an endpoint, both keep animating through the joint.
• If two lines run on top of each other for part of their length, only one of them draws its moving pattern on the shared part. This stops the overlap from looking cluttered.

What does not animate

Lines with an arrow on both ends cannot be animated. An arrow at each end means the line points both ways, so a travel direction would not make sense. These lines stay still, and the picker does not offer an animated version of them.

Saving, sharing and exporting

Animation is saved with your map. Anyone who opens the map in Scribble Maps sees the lines moving.

Still images do not move, so exports, prints, image downloads and map thumbnails show the line without animation. The line itself, along with its colour, width and arrows, looks the same as it does on the map.

Legends

If you add an animated line to a legend, the legend swatch animates too. This helps readers match the moving line on the map to the matching entry in the legend.