HOW TO MAKE Accessible Complex Images
Complex images include graphs, charts, diagrams, maps, and illustrations. Below are three ways to provide alternative (alt) text-based description for complex images, when a simple alt text attribute is insufficient. Choose the best alt text method for your image types.
B
C
A
Describe in surrounding text
Link out to a web page with a longer description
Use a caption
If the image cannot be described using methods A or B, use the ‘longdesc’ attribute (requires HTML editing). Example code: <img src=”images/fig9.jpg” alt=”Fig.9- Graph of the length of daylight from March 21 through December 21 at various latitudes.” width=”400” height=”290” longdesc=”fig9-longdesc.html ” />
For Web Pages: Your caption must be associated with the image, so make sure to properly add a caption using the ‘ figcaption ’ html tag. (Requires HTML editing). Note: For MS Word and PowerPoint: Right click on the image and select Add Caption . Example Code: <figure><img src=”images/fig9” alt=”” width=”160” height=”120” /> <figcaption><em> Caption goes here, Fig.9-Graph.. </em></figcaption></figure>
If the image is adequately described in surrounding text (including text-based data tables), so that the image is just reinforcing the text, no further description is needed
necessary. Example:
Modeling amount of daylight as a function of time of year, Figure 9 and the table beside it, show the number of hours of daylight as functions of the time of the year at several latitudes, from March through December.
Month Hours in varied latitudes 20° 30° 40° 50° 60° Mar 12 12 12 12 12 Apr 12.3 13.2 13.5 14 17.5 May 12.9 13.7 14.3 15.5 17.7 Jun 13 14 14.9 16.1 18.2 Jul 12.8 13.8 14.2 15.7 17.8 Aug 12.5 12.8 13.2 14 15 Sep 12 12 12 12 12 Oct 11.6 11.2 10.8 10 9 Nov 11 10.2 9.7 8.3 6.5 Dec 10.9 10 9.1 7.9 5.7 Example of Data Table for Figure 9
<html> <p>Modeling amount of daylight as a function of time of year Figure 9 shows graphs of the number of hours of daylight...</p> </html>
Figure 9
Figure 9
Fig.9 - Graph of the length of daylight from March throughDecember at various latitudes. For example, at 40 degree latitude there are 12 hours of daylight in March. In October, there are 10.8 hours of day- light at 40 degree.
fig9-longdesc.html
8 A
The graph image is from Lucia C. Harrison, Daylight, Twilight, Darkness and Time (New York: Silver, Burdett, 1935) page 40.
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