This architectural drawing is Longitudinal section of tunnel with detailing. A tunnel is relatively long and narrow; the length is often much greater than twice the diameter, although similar shorter excavations can be constructed, such as cross passages between tunnels. Longitudinal studies and cross-sectional studies are two different types of research design. In a cross-sectional study you collect data from a population at a specific point in time; in a longitudinal study you repeatedly collect data from the same sample over an extended period of time. The 'Longitudinal Section' drawing is used to show the vertical relationship between the designed and existing surfaces. The drawing is also used to show the geometric details of the reference string involved. For more details and information download the drawing file.
