Line layers

Line feature layers can be added into an AGOL scene by, again, first adding them into your Content area, then selecting them from within the Scene Viewer interface using the ‘+’ button.

Line feature layers have their own unique options within the ‘Layer types’ pane. The options offered will be dependent upon whether the line feature layer, itself, has been supplied with a 2D or 3D geometry.

If you’re using 3D data, but are also using an attribute for feature classification, the ‘Layer type’ display may revert to apparently offering the ‘2D Types’ and ‘3D Types’ options. We assume that this is an error with the user interface only, as the functionality does not appear to be affected.

If you’re working with 2D data, the available ‘Layer type’ options should look like this:

2D types and 3D types shown using OS Open Zoomstack Roads data.

Alternatively, if you’re working with a 3D line layer, you should instead see these options:

2D line and 2D path options shown using OS NGD Transport Links data.

Examples of each option are thus described below.

‘2D Types’ (for 2D layers only)

The ‘2D Types’ option renders the line features as 2D draped lines. When used alongside a mesh, it can be an effective solution when viewed from afar. However, as the following figures show, it can look rather odd when viewed close-up.

The '2D Types' option, when viewed from a distance.

Line feature, in '2D Types' mode, when viewed from close by. Such issues are particularly problematic in areas dominated by vegetation.

If using this mode, it’s certainly worth experimenting with different line widths, as it’s often easy for detail to be lost amongst the complexity of a 3D mesh.

‘3D Types’ (for 2D layers only)

The ‘3D Types’ option will render line features as a solid geometry. By default, this will be realised as a set of ‘tubes’, but different shapes are available, should you prefer a rectangular or square profile. As with ‘2D Types’, there is also the option to specify different line widths.

A lines rendered in '3D Types' mode. In this example, a square profile has been chosen, giving the line features a more angular look.

The ‘3D Types’ option also undergoes a degree of mesh draping. However, for this option, the result seems to be much generalised in comparison. Thus, if viewed close-up, the ‘tubes’ may be seen to pass directly through a tree canopy, rather than conform to its outer edges:

Line features rendered in '3D Types' mode. Notice that although the line's path is affected by the overhanging tree, it doesn't attempt to fully deform around it.

‘2D Line’ (for 3D layers only)

In this option, line features will be rendered very simply, as if they were lines on a page, albeit in 3D space. As the supplied line layer will already contain its own height data, no attempt to drape the features will be made. As such, there will no direct dependency on the mesh, assuming one is present. This, of course, will eliminate the potentially unwanted behaviours discussed in the previous sections. However, there may, instead, be occasions where the line features dip below the mesh’s surface in ways that are not wanted.

A 3D line feature set (OS NGD transportation links…), as rendered with the ‘2D Line’. At the bottom-left of the screen, an example can be seen of a road falling under the mesh.

‘3D Path’ (for 3D layers only)

Like the ‘3D Type’ option covered previously, this option will render lines as solid objects, using the shape profile of your choice. Again, because full 3D geometry is present, no draping is undertaken, with the vertical position relying entirely on the layer’s own geometry. This option can potentially solve the ‘below the surface’ issue mentioned above, with the line thickness making it more likely that the layer will remain fully visible.

Line features rendered with the '3D Path' option. In this example, a square profile has been chosen. Additionally, a 50% transparency has also been applied.