Figures and tables (display items) are often the quickest way to communicate large amounts of complex information that would be complicated to explain in text.
Many readers will only look at your display items without reading the main text of your manuscript. Therefore, ensure your display items can stand alone from the text and communicate clearly your most significant results.
Display items are also important for attracting readers to your work. Well designed and attractive display items will hold the interest of readers, compel them to take time to understand a figure and can even entice them to read your full manuscript.
Finally, high-quality display items give your work a professional appearance. Readers will assume that a professional-looking manuscript contains good quality science. Thus readers may be more likely to trust your results and your interpretation of those results.
When deciding which of your results to present as display items consider the following questions:
Are there any data that readers might rather see as a display item rather than text?
Do your figures supplement the text and not just repeat what you have already stated?
Have you put data into a table that could easily be explained in the text such as simple statistics or p values?
Tables are a concise and effective way to present large amounts of data. You should design them carefully so that you clearly communicate your results to busy readers.
- The following is an example of a well-designed table:
- Clear and concise legend/caption
- Data divided into categories for clarity
- Sufficient spacing around columns and rows
- Units are provided
- Font type and size are legible
Source: Environmental Earth Sciences (2009) 59:529–536
Figures are ideal for presenting:
- Data plots
Just like tables all figures need to have a clear and concise legend caption to accompany them.
Images help readers visualize the information you are trying to convey. Often, it is difficult to be sufficiently descriptive using words. Images can help in achieving the accuracy needed for a scientific manuscript. For example, it may not be enough to say, “The surface had nanometer scale features.” In this case, it would be ideal to provide a microscope image.
For images, be sure to:
- Include scale bars
- Consider labeling important items
- Indicate the meaning of different colors and symbols used
Data plots convey large quantities of data quickly. The goal is often to show a functional or statistical relationship between two or more items. However, details about the individual data points are often omitted to place emphasis on the relationship that is shown by the collection of points. Here, we have examples of figures combining images and data plots in multiple panels.
For data plots, be sure to:
- Label all axes
- Specify units for quantities
- Label all curves and data sets
- Use a legible font size
Maps are important for putting field work in the context of the location where it was performed. A good map will help your reader understand how the site affects your study. Moreover, it will help other researchers reproduce your work or find other locations with similar properties. Here, we have a map used in a study about salmon.
For maps, be sure to:
- Include latitude and longitude
- Include scale bars
- Label important items
- Consider adding a map legend
Schematics help identify the key parts to a system or process. They should highlight only the key elements because adding unimportant items may clutter the image. A schematic only includes the drawings the author chooses, offering a degree of flexibility not offered by images. They can also be used in situations where it is difficult or impossible to capture an image. Below is a schematic explaining how nanotubes could be used to harvest energy from a fluid.
For schematics, be sure to:
- Label key items
- Provide complementary explanations in the caption and main text
Avoiding image manipulation
You should never knowingly manipulate your images to change or improve you results. To avoid inadvertent manipulation you should only minimally process your figures before submitting them to the journal, your submitted images should faithfully represent the original image files.
Adjusting the brightness or contrast of an image, in fluorescent microscopy for example, is only acceptable if applied equally across all images including the controls
The cropping of images in the creation of figures should be avoided unless it significantly improves the clarity or conciseness of presentation. Be sure that the cropping does not exclude any necessary information for the understanding of the figure, such as molecular markers in electrophoresis gels.
Any adjustments or processing software used should be stated.