"illustrate the direction" is a perfectly correct and usable phrase in written English.
For example, you could use this phrase in a sentence such as: "The map clearly illustrates the direction of the river."
The weights and directions illustrate the direction of the dialog in the movie.
The panorama images illustrate the direction of scratch testing, and the morphologies of the entire scratches are shown in Figure 8a, b, c, d.
The load as a function of indentation depth during the whole process of indentation and subsequent retraction is plotted in Fig. 2. The arrows illustrate the direction of motion of Ni tip.
Regression coefficients are reported below, with interactions graphed to illustrate the direction of effects.
The purpose of this study was to validate a research-based Sociocultural Health Behavior Model (SCHBM) using Structural Equation Analysis (SEM) to illustrate the direction and magnitude of the SCHBM components in relation to HBV screening among Asian Americans.
To illustrate the direction and shape of associations, age-adjusted means and prevalences of breast cancer and possible confounding factors were estimated across quarters of height and each component of height.
The lateral etch rate diagram is used to illustrate the directions of undercutting at the free end and the <100> mask edges.
Mr. Hall said that over the past nine months the iPad has illustrated the direction television is going in.
This kind of overloaded metadata outside the 140 character window illustrates the direction Twitter is having trouble moving to even as it tweaks its static interface by abandoning user options.
The exercise is simple: I simply ask Creative Intelligence to bring forward some word that best illustrates the direction for the coming 12 months.
The first motif is an upward scale, illustrating the direction Heaven, played by the first violin, imitated in fast succession by the second violin and then the continuo.
