As shown in Table3.8graphics orfigures resp. have three possible functions. They shall either simplify reality (e.g. principle drawing, map), or explain abstract ideas by means of spatial arrangement (e.g. bar chart, pie chart, tree chart), or create associations (e.g. logo and pictogram).
Figures are often too little exact for these information purposes, but they have instructional advantages due to their similarity with the optically recognized world. In most cases it is especially effective, to present the overview information infigures and the detail information as text. To prevent misunderstandings and wrong interpretations of your readers, you should keep the following basic rules for figure design. If you keep these 13 basic rules, this is already a big step towards“good”figures.
13 Basic rules for information-effective design offigures 1. Accentuate important items!
2. Delete/leave out unimportant items! (use max. four to seven graphic elements in one picture, otherwise the picture becomes overloaded.) 3. Line thickness and font size must be sufficient! (Thefigure shall be readable
without problems from the normal reading distance of 30–40 cm.)
4. The eye follows dominant lines. Therefore, relationships of graphic elements shall be emphasized (lines, arrows, columns, rows, common color). These relationships should also be specified in detail (What is the character of the Table 3.8 Systematic structure of graphic displays according to function and contents
Graphics
Schemes (simplify reality) –symbol
–principle drawing –block diagram –function scheme –flow chart of a process –org chart
–map
–wiring diagram, hydraulic diagram, pneumatic diagram, piping diagram
–technical drawing –sketch for computations –perspective drawing (incl.
explosion drawing) –comic
Diagrams (explain abstract ideas) –bar chart –point chart
–line chart, e.g. graph of a function, nomogram –circular chart or pie
chart –area diagram –body diagram –Venn diagram –tree diagram –Gantt diagram –network plan –flowchart –structogram –mind map
Icons (create associations) –concrete pictogram (shows
items or animals or persons)
–abstract pictogram (shows abstract terms, must be learned)
–symbol –logo –traffic sign –information sign –etc.
relationship? What does it mean?) by means of labels in the figure or explanations in the legend.
5. Spatial closeness of elements is understood as conceptual similarity (objects near to each other belong together).
6. Elements, which are placed above or below other elements, are interpreted as hierarchically super-ordinated or sub-ordinated. This emphasizes func- tional structures.
7. Elements, which are placed beside each other, are interpreted as time or logical sequence.
8. If the elements are arranged in a circle, this appears as a cycle, a frequently repeated sequence.
9. If one element surrounds another element, this is understood in such a way that the exterior term semantically includes the interior term.
10. Elements like boxes, bars, lines, columns must be clearly marked (either by text labels or by graphical explanations/pictograms).
11. One type of element may have only one function within onefigure orfigure series. For example arrows can be used for the following types of information:
– direction of force, – moment of torque, – direction of movement, – flow of information, – cause and effect, – note etc.
The different meaning of the arrows shall be visible due to a different graphical design of the arrows. So, double arrows are used to express a cause and effect relationship. If in the samefigure you also want to draw a double arrow for a moment of torque, this arrow must look much different and the difference must be communicated to the reader.
12. Axes have large figures on the (vertical) y-axis at the top and on the (hor- izontal) x-axis on the right side.
13. For some diagram types, there are standardized symbols. Example: DIN 66001 for flow charts defines that a rectangle is used for an operation, a diamond for a decision and a rounded rectangle for start and end of a procedure. Other standards: DIN 32520, DIN 66261. Naturally speaking, such standards must be applied.
The application of basic rules 1 and 2 is also called“didactic reduction”.
By leaving out and simplifying information, the reader can concentrate on what is important, following the motto“Something that is not shown cannot be misunderstood.” When designingfigures, you can apply the following measures in addition to accen- tuate parts of thefigure and to influence the reading sequence:
– Color: Colors can be remembered much better than section lining, different line thicknesses or line types. Red is the most popular and most striking color. Please use color very careful to avoid overshooting the target. And keep in mind: Colored objects and lines appear much different, when printed in black-and-white, because the printer changes colors to grayscale values.
– Arrows: There are many graphic design variants available for arrows. Arrows can point out important details. Arrows can also have other functions, see rule 11.
– Oversize: Details, which are not eye-catching, but important, are displayed larger and unimportant details are left out or displayed pale or blurry. The scaling factor of a detail within a normally (100%) sized environment can be raised up to 1.5 (150%) without irritating the reader.
– Line thickness: Important elements are drawn with 0.75–1.50 mm thick lines. Less important details appear with a line thickness of 0.25–0.50 mm.
– Framing: To accentuate important details, they can be framed or marked with a circle.
– Detail enlargement: A rectangular or circular frame is repeated in the samefigure or (not so good solution) in a secondfigure (magnifying glass). The connection between the segment in original size and the enlarged segment must be recognizable (con- necting lines). The frames must be similar (e.g. rectangle with constant width-to-height-ratio or circle) so that the reader can assign the segment of thefigure in original size and the enlarged segment with each other.
– Colored background or shading: An important section of thefigure gets a colored or gray background. In this case the contrast between object(s) in thefigure and back- ground must be sufficient.
▸ Please use only a few of these measures to accentuate parts of thefigure and to influence the reading sequence. Otherwise, the figure might become confusing. Do not accentuate too many details. Otherwise, the influence on the reading sequence might get lost.
If you design yourfigures or modifyfigures from literature sources according to the 13 basic rules, also apply the measures to influence the reading sequence. Then your readers can recognize and interpret the message of your pictures much easier. Your figures become better understandable. Your message sent out as a figure reaches your readers much better and exactly in the intended way.