| Spatial Selection |
| X |
| X |
| 8 |
| X |
| X |
| X |
| X |
| X |
| X |
| X |
| X |
| 6 |
| X |
| X |
| X |
| X |
| X |
| X |
| X |
| 4 |
| X |
| X |
| Price |
| $8,000 |
| $40,000 |
|
|
| Hierarchical:
One axis can code multiple attributes |
|
| (Milhalisin et al.,
1991) |
|