6.5: [Example] Formatting Accessible Tables
This set of examples is used to illustrate common errors when formatting tables in Pressbooks, and how these can be fixed. These examples includes a information developed by
The Story of Earth: An Observational Guide by Daniel Hauptvogel & Virginia Sisson. Our thanks to the team at Daniel Hauptvogel, Virginia Sisson, and their team.
Original Tables from “The Story of Earth”
In Table 1.1, the header cells are marked using bold formatting, instead of the scoping attribute. This makes it difficult for screen readers to process this information. Instead, we’ve reformatted the information in Table 1.3 to properly mark the header rows and columns.
Table 1.1 – Comparison of oceanic and continental crust.
| Property |
Oceanic Crust |
Continental Crust |
| Thickness |
7-10 km |
25-80 km |
| Density |
3.0g/cm3 |
2.7g/cm3 |
| Silica (SiO2) Content |
50% |
60% |
| Composition |
Fe, Mg, and Ca silicates |
K, Na, and Al silicates |
| Color |
Dark |
Light |
In Table 1.2, the merged cells may prove difficult to read by a screen even if properly marked. So instead, reformat the table as shown in Table 1.4 and 1.5
Table 1.2 – Earthquake location data from Chile (from Martinod et al., 2010)
| Chile-Peru Border |
Central Chile |
| Distance from trench (km) |
Depth (km) |
Distance from trench (km) |
Depth (km) |
| 200 |
30 |
170 |
40 |
| 220 |
50 |
220 |
65 |
| 300 |
65 |
400 |
90 |
| 370 |
125 |
200 |
50 |
| 500 |
190 |
120 |
20 |
| 300 |
100 |
500 |
110 |
| 250 |
65 |
350 |
85 |
| 210 |
40 |
300 |
75 |
| 280 |
80 |
250 |
60 |
| 450 |
175 |
280 |
75 |
| 400 |
140 |
200 |
55 |
| 410 |
150 |
260 |
90 |
Reformatted Tables for improved accessibility
Table 1.3 – Comparison of oceanic and continental crust.
| Property |
Oceanic Crust |
Continental Crust |
| Thickness |
7-10 km |
25-80 km |
| Density |
3.0g/cm3 |
2.7g/cm3 |
| Silica (SiO2) Content |
50% |
60% |
| Composition |
Fe, Mg, and Ca silicates |
K, Na, and Al silicates |
| Color |
Dark |
Light |
Table 1.4 – Earthquake location data from Chile-Peru Border (from Martinod et al., 2010)
| Distance from trench (km) |
Depth (km) |
| 200 |
30 |
| 220 |
50 |
| 300 |
65 |
| 370 |
125 |
| 500 |
190 |
| 300 |
100 |
| 250 |
65 |
| 210 |
40 |
| 280 |
80 |
| 450 |
175 |
| 400 |
140 |
| 410 |
150 |
Table 1.5 – Earthquake location data from Central Chile (from Martinod et al., 2010)
| Distance from trench (km) |
Depth (km) |
| 170 |
40 |
| 220 |
65 |
| 400 |
90 |
| 200 |
50 |
| 120 |
20 |
| 500 |
110 |
| 350 |
85 |
| 300 |
75 |
| 250 |
60 |
| 280 |
75 |
| 200 |
55 |
| 260 |
90 |