The A-frame level is one method of laying out a contour line. It has 2 legs, and a weight hanging from a string in the center. Both legs are at the same elevation when the string lines up with a mark on the horizontal strut.
| File size | : | 1397177 bytes |
| File date | : | 2004:10:28 00:25:32 |
| Camera make | : | NIKON |
| Camera model | : | E4500 |
| Date/Time | : | 2004:10:23 17:00:19 |
| Resolution | : | 1704 x 2272 |
| Flash used | : | No |
| Focal length | : | 8.9mm |
| Exposure time | : | 0.014 s (1/73) |
| Aperture | : | f/3.1 |
| ISO equiv. | : | 100 |
| Metering Mode | : | matrix |
| Exposure | : | aperture priority (semi-auto) |
| Jpeg process | : | Baseline |