In 1903, Julius Neubranner, a photography enthusiast, designed and patented a breast-mounted aerial camera for carrier pigeons. Weighing only 70 grams, the camera took automatic exposures at 30-second intervals along the flight line flown by the bird. Although faster than balloons, they were not always reliable in following their flight paths. Today the pigeon corps has been replaced by unmanned aerial vehicles, but aerial photography continues to be an important source of data for use in a wide range of geospatial applications. Processing of the imagery to remove various types of distortion is a necessary step before the images can be georeferenced and used for mapping purposes.
The interpretation of images that are created according to electromagnetic energy reflected from or emitted by earth surface features or atmosphere is a common practice to obtain useful information from raw image data. Images acquired by a device that is not in contact with objects and features are generally referred to as remotely sensed data, and the photo interpretation is generally carried out to extract meaningful information from image data for any subsequent uses. Specifically, this chapter covers elements of image interpretation, photo interpretation key, scale of an aerial photograph, heights, distances, and areas of objects in a photo, and land use land cover classification and mapping.