Types of photography useful in natural hazard management
Vertical (or oblique) aerial photos: when taken as a series, these can be used to illustrate the features of concern, and highlight differences that have occurred over a period of time (for example, the erosion of coastlines over time).
Orthophotos: aerial photos with the distortion removed, and related to specific points on the ground. When overlaid with LIDAR (Light Detection and Ranging: a system used to measure the elevation of a surface, with greater than 1 metre accuracy), an accurate representation of the land use can be made in relation to natural hazards.
Orthophotos overlaid with LIDAR have the advantage of being able to be vertically exaggerated and manipulated as required.
Path of the 2007 lahar down the Whangaehu River valley
The photograph above shows the Whangaehu River channel at the location of the Round the Mountain Track (Tongariro National Park). It shows the path the 2007 lahar took down the Whangaehu River valley. This is an example of a digitally enhanced map from a LIDAR survey draped with a vertical orthophoto.
