Graphics Guide

Figure files should be submitted as vector Encapsulated PostScript (EPS) or Portable Document Format (PDF). Scalar (PNG, JPG, TIFF) formats are also acceptable, but the author should submit files with resolutions that would result in at minimum 300 DPI on the final PDF page. Such a figure file would have at minimum 1000 pixels of horizontal resolution.  Each figure file should consist of a single page. Authors are responsible for splitting multipage EPS and PDF files into many separate page files. This can be done automatically with Adobe Acrobat, manually with OS X’s Preview, or various free online tools.

If you are using AASTeX, you should use AASTeX’s guide to include the figures in the TeX file. You should also embed the figures if you are using Microsoft Word to prepare your manuscript, but separate figure files are still required at final submission.

Each figure set, animated, or interactive figure requires a static two dimensional representation rendered in the LaTeX/Word manuscript. It should have its own numbering, descriptive caption, etc. The static version (e.g., f1.pdf) should be uploaded as a regular figure and separate from the dynamic elements (mp4 files, HTML files, javascript libraries, data), which should be bundled as a zip file, e.g., fig01anim.zip, fig03int.zip, fig07set.zip, etc.

We recommend that authors familiarize themselves with best practices for the creation and accessibility of scientific visualizations. Resources, including “Ten Simple Rules for Better Figures,” should be consulted to improve the impact and readability of your figures. Specifically, we call out Rougier et al.’s Rule 5: Do Not Trust the Defaults, and strongly encourage you to check the color defaults used by your preferred visualization software. Regarding accessibility, Katsnelson’s “Colour me better: fixing figures for colour blindness” provides a great overview of the impacts of inaccessible figures with corresponding fixes authors can proactively make. Tools such as Color Oracle should be utilized to check your figures for accessibility before submission; correcting your figures may be achieved by adopting color maps such as viridis, e.g., the default colormap in matplotlib 2.0 default, which is also available for R via CRAN, or cube-helix (Green 2011), which is available in some astronomy software tools such as AIPS or Aladin. The public domain R statistical and graphical software environment has flexible color options with 657 color names and palettes based on the Color Brewer, Hue-Saturation-Value and Hue-Chroma-Luminance systems. See R guidelines here (PDF) and here (PDF). Use of unsaturated colors is recommended when symbols overlap in crowded diagrams; this requires the PDF rather than EPS formats.

When we prepare the published version of your manuscript we may rearrange or resize the figures, so it is helpful if you can ensure that each figure or subfigure is in a separate file. If a figure is part of a lettered, multipart figure, place the letter within the box around the figure, not outside of it. If the letter cannot be placed within the box, lettered tags can be typeset. Page numbers, figure numbers, file information, etc., should not be included in figure files.

If you feel that figures in the published article must be sized or arranged in a certain way, please include a

readme.txt

file which describes your requirements; the Production Editor may contact you about this when the manuscript is accepted. Note that extra charges will be incurred if you decide to make alterations to figures at proof stage.

Additional guidelines and tools include:

Fonts, lines, symbols

Try to use only common fonts, such as Times, Helvetica, or Symbol, in figures. Spelling and use of numbers and units in figures should conform to usage in the body of the text and figure legends. A minimum of 6 pt. font size is acceptable. There should be consistency of appearance between the size of symbols and the size of type within a figure, and between the weight of the lines and the weight of type within the figures. Lines in figures should be at minimum 0.5 points, and if you use dotted or dashed lines you should check that the different sorts of lines are distinguishable when the figure is small.

More on Color Accessibility

The use of color as the only distinguishing delimiter in a figure should be generally avoided. Colored lines should also use different line styles; colored symbols should be varied in shape, colored histograms use different hatching or weights. These types of choices greatly enhance the usability of a figure for a low-vision or color-blind reader or for a reader who can only utilize the resulting manuscript in greyscale.

AASTeX Specific Advice

Instructions for structuring and placing figures using AASTeX are available. Users of AASTeX 6.3+ will find a new LaTeX command \interactive for tagging animated and interactive figures directly in their LaTeX files.

Finding figures from AAS Journals articles:

We have centralized all the figures in articles from all AAS Journals since ~1997 on our Astronomy Image Explorer (AIE) tool. The figures from your final article are posted at the AIE at publication sans embargo. They are provided in high resolution JPG, PDF, and PPT formats. As a result the NASA ADS has integrated these graphics into their article landing pages (e.g., Mao et al. 2015) and link back to the AIE for each regular figure.

A figure set is the frame work used to present a large compendia of similar images and graphical material in the HTML version of your final article. They have the added author benefit of simplifying quanta charges for related figures. Examples include identification charts, spectral libraries, model output, etc. Figure sets should be used when a single Figure exceeds four typeset print pages. The figure set functionality gives the reader the ability to quickly find specific images within the figure set sequence; thus, it is well suited in cases with many similar images.

To facilitate the layout of the final article, the figure set components and associated information need to be placed in the appropriate AASTeX/LaTeX mark up. This LaTeX markup is included in AASTeX >6.0, and allows you to craft individual titles and captions for each figure in the set. Figure sets must be mentioned explicitly by number and appear in correct numerical order in the body of the text. At least one image in a series must be displayed as an example static figure in the PDF version of the final article. The corresponding caption should indicate that additional images are available in the Figure set. For example,

"The complete figure set (11 images) is available in the online journal.

The example figure should be placed after the figure set mark up in the LaTeX file and created like a normal figure, e.g., \begin{figure}…. An online tool is available to help create the figure set mark up, as is a python script located at our github “Tools” repository.

Please submit all figure set figures in a single ZIP archive, e.g., fig01set.zip. Do not submit hundreds of figure set files individually (unless you think the referee needs to see them in the PDF used for peer-review). If you craft the LaTeX script yourself then also include it in the ZIP archive. The data editors will review this material post-acceptance.

For reference purposes, a list of published articles with figure sets (>1100) in the AAS Journals can be found using our Astronomy Image Explorer by toggling the “Content Type => Figure sets” search facet.

We now support animations as regular figures in AAS Journal articles. Animated Figures are presented using a streaming YouTube like widget that works in all major browsers and on mobile platforms. As with regular Figures, animations can now be referred to by number, e.g., Figure 1, and subsequently linked in the final text. Readers click through from the static Figure to the streamed animation. We strongly recommend that a Figure contain one and only one animation due to issues readers face when interacting with multiple animations on a page. There are some specific steps authors should follow:

Static Figure

Authors mark up an animated figure as they would any other figure in their manuscript file. Users of AASTeX 6.3+ will find a new LaTeX command \interactive for tagging animations directly. You must supply a static representation of the animation in an acceptable file format. The recommended way to do this is to provide a single “example” frame or grid of stills from the animation. Note that the content of the static and animated versions should closely agree, including the aspect ratio of two versions.  Other uses of animations that do not correspond to actual Figures in the final article should be hosted external to the Journals in persistent third party repository and linked to the corresponding text.

Accessibility and Captions

The caption of an animated figure must include text describing the animation and indicating that it is available in the HTML version of the final article. For instance, text such as “An animated version of this figure is available” is insufficient and should be followed with a short description of the animation itself — duration (in time or other units), how the content changes with time, presence of annotations, etc. The caption should also detail any differences between the material shown in the static and dynamic versions of the figure. This explicit description is critical for readers for whom the animation is inaccessible either due to a disability or offline access.

Animation file(s)

We strongly recommend animations be delivered in the MPEG-4 container, specifically encoded with the H264 codec. Other formats may be used (except for animated GIFs); however, using MPEG-4 will provide the most faithful rendering of your video in the journal article. A single movie per Figure should be optimized to fit within the typical Journal page and not overburden low bandwidth or mobile users. We recommend authors consider that the streaming widget will initially display the inline movie with a width of approximately 600 pixels, though the reader will also be able to view the original file at full screen. The recommended parameters for submitted animations are:

The tools we find most useful for managing these animation parameters include the Handbrake application and the ffmpeg software. Tips for using both applications are given below.

A list of published articles with videos (>3500) in the AAS Journals can be found using our Astronomy Image Explorer by toggling the “Content Type => Videos” search facet on the left hand side.

Interactive figures give the reader the ability to manipulate the information contained in an image, which can add clarity or help further the author’s narrative. These figures consist of two parts, the static figure file for the L^aT_eX/PDF copy and a dynamic Javascript and HTML framework that provides interactive control. The basic requirements for these figures are:

An example of an interactive figure is a 3D model. The underlying figure data is an X3D file while x3dom.js is the javascript driver that displays it. An author created interface is added via an HTML wrapper. The first 3D model published by the AAS Journals using this technique was Vogt et al. (2014). Vogt et al. have published a 2016 ApJ article entitled, “Advanced Data Visualization In Astrophysics: The X3D Pathway,” that more fully illustrates the power of X3D data objects and graphics.

The AAS has partnered with astropy to create a new package, aas-timeseries, that can produce interactive figures of any time series data set. Authors can create interactive figures with different layers, specific markers and ranges plus lines and labels. All of this functionality serves to help the author guide the reader to interesting regions of the graph while still allowing the reader the flexibility to explore other regions and have access to the underlying data.

Authors should consult online tutorials for more information on how to construct their own interactive figures. AAS Journal Data Editors can provide limited support via our ticket system. The current list of supported HTML/JS frameworks include:

There are some specific additional steps that authors should follow:

Static Figure

Authors mark up an interactive figure as they would any other figure in their manuscript file; however, users of AASTeX 6.3+ will find a new LaTeX command \interactive for tagging interactive figures. Details are available here. In any case you must supply a static representation of the interactive figure in EPS/PDF format encoded as a regular figure to serve as a reference for the reader. It is best practice for this static version to be a single “example” screenshot from the interactive figure.

Accessibility and Captions

The caption of an interactive figure should include text describing the interactivity and indicating that it is available in the HTML version of the final article. For instance, text such as “This figure is available online as an interactive figure” should be followed with a short description of the interaction itself — what exactly is displayed, colors, controls, annotations, etc. This explicit description is critical for readers for whom the interactive figure is inaccessible either due to a disability or web access.

Interactive file(s)

Please submit all interactive figure materials in a single ZIP archive, e.g., fig03int.zip. The AAS Journal data editors will place your graphic on a webserver for testing before transferring it to IOP publishing for final insertion into your manuscript. Alternatively, include a URL link in your submission metadata to a hosted version of your graphic. This upload should include the source data represented by the interactive figure. See also Tips below on preparing interactive figure submissions.

For reference purposes, a list of published articles with interactive figures (>80) in the AAS Journals can be found using our Astronomy Image Explorer by toggling the “Content Type => Interactive Figures” search facet.

Here are some specific tips for using Astropy to create graphics for the AAS Journals.

aas-timeseries

There is a specific procedure for generating the necessary files for an interactive time series figure using the aas-timeseries package in astropy.

First export the interactive figure(s) to a zip file with the command:

fig.export_interactive_bundle('my_figure.zip')

Next, use this command to export the static version of the figure:

fig.save_static('my_figure', format='pdf')

where “my_figure” can be any descriptive identifier.

ffmpeg is a powerful and sometimes overwhelmingly complicated piece of software for editing movies. At the AAS Journals we use this software to do things like switch codecs for animations, up the frame rate of an animation by duplicating frames, and merge multiple time-synchronized movies into single animations that fit into the final Journal article. Some examples of our use of ffmpeg are given here:

• Given a large, low framerate MPEG-1 encoded file, change codecs, resample to 30 fps, and set CRF compression to 18
  

  • ffmpeg -i figure1.mpg -c:v libx264 -pix_fmt yuv420p -r 30 -crf 18 fig1anim.mp4

• Change the average bitrate to 3M/s using ffmpeg to reduce file size (if originally very high) or artificially upsample image quality (if originally very low, under 800Kps), while setting the frame rate to 24 fps. More information from the ffmpeg documentation.
  

  • ffmpeg -i figure3.mp4 -b:v 3M -r 24 fig3anim.mp4

• convert an animated gif to an mp4 video with 30 fps

  • ffmpeg -i animated.gif -movflags faststart -pix_fmt yuv420p -vf "scale=trunc(iw/2)*2:trunc(ih/2)*2" -r 30 video.mp4

• merge two different AIA observations of the same UT and clock duration into a single horizontally oriented animation that fits nicely on the final Journal webpage

  • ffmpeg -i AIA94.mpg -i HMI.mpg -filter_complex hstack \ 
    -c:v libx264 -pix_fmt yuv420p -r 30 -crf 18 fig1anim.mp4

We use the following settings for the Handbrake application when editing author submitted animations that do not match the file requirements listed above:

Not all PostScript (PS) files are Encapsulated PostScript (EPS) files; in particular, an EPS file must contain a bounding box. Incorrectly constructed EPS files can cause problems when trying to combine the text with all the figures into one single PS file. Check the documentation for your graphics software to ensure that it does genuinely output compliant EPS files, and, in particular, please note that a PS file created by printing to file from the Windows or Macintosh operating systems will probably create a problematic PS file.

The R statistical software environment (http://www.r-project.org) has extensive publication-quality graphics capabilities. A common procedure uses the plot function followed by the dev.copy2eps function to deposit the graphic onto the disk in EPS format. Usage of plot is illustrated by the following: plot(x, y, pch=20, cex=0.6, col='crimson') where pch defines symbol shape, cex defines symbol size, and color names are given at http://cloford.com/resources/colours/500col.htm. Unsaturated colors, useful when points overlap, are specified like col='B0171F20', but needs be indirectly converted to EPS through the PDF format. R also incorporates the ggplot2, lattice, rgl, and other graphics systems, as well as a variety of image, 3-dimensional visualization, and animation capabilities.

Recommended Resources:

When using SuperMongo (or any varieties of the Mongo program), a small bold font should be used for axis labels, lettering, etc., rather than the default “outline” font. The lines that make up the outline font are very thin and may drop out during the publication process.