Since the accuracy of the coordinates varies according to the precision of source information, users should inspect the preview image to verify that the area of interest is contained in the selected frame. CoordinatesĪerial photography mosaics and flight line maps were used to approximate geographic location. Images intended for cartographic use typically have a 60% overlap of images within a flight line to allow for stereographic viewing with specialized equipment. The horizon is visible in high oblique images, which are taken at a depression angle of 60°, but not in low oblique images, which are taken at a depression angle of 30°. Oblique images are taken with the camera pointed at an angle and offer a different perspective, which provides an additional tool for interpretation of landscape features like shape and texture.
![aerial photos aerial photos](https://assets.londonist.com/uploads/2019/01/i875/jasonhawkes-181777_original.jpg)
![aerial photos aerial photos](http://www.sussexphotos.co.uk/library/large/12401.jpg)
The majority of the USGS EROS film collection is vertical photography, which is obtained with the camera pointed at the ground. The recording technique can be vertical or oblique. Recording TechniqueĪerial photographs are acquired by aircraft equipped with mapping cameras. Users should note that the images have not been georeferenced. The images in the Aerial Photography Single Frame Records collection may have feature displacement and scale variation caused by differences in elevation, lens distortion, and camera tilt. The photographs in this collection were acquired by a variety of Federal agencies for a wide range of applications and have scales ranging from 1:1,000 to 1:199,000. An image with a scale of 1:8,000 would cover a smaller area on the ground with the landscape details appearing larger than an image with a scale of 1:24,000. An image with a scale of 1:24,000 means that one inch in the photo is equivalent to 24,000 inches on the ground. The scale of the image is the ratio of the distance on the image compared to the equivalent distance on the ground.
#AERIAL PHOTOS FULL#
The medium and high resolution scanned images are captured as they appear on film and are representative of the full tonal range of the original film source. CIR photography utilizes high speed film that is subject to degradation prior to processing, which can create an overall blue cast to the image. Vegetation is distinctly red to magenta in color infrared images because vegetation is highly reflective in the near-infrared portion of the spectrum. Color photography is a valuable image interpretation tool with a wide range of applications since the imagery is a close visual reproduction of the original scene.Ĭolor infrared (CIR), or false color film, is sensitive to green and red in the visible portion of spectrum of light and extends into the near-infrared region of the spectrum. Vegetation appears white to light gray in black-and-white infrared images.Ĭolor film is sensitive to blue, green, and red in the visible region of the electromagnetic spectrum of light and has the appearance of natural color.
![aerial photos aerial photos](https://s3-us-west-2.amazonaws.com/axiomimagesthumbs-or/proxy/original/AX80_097-00001.jpg)
Near-infrared wavelengths differentiate various types of vegetation, penetrate atmospheric haze, and show good contrast between land and water. This is the most widely used type of film in the USGS EROS film archive.īlack-and-white infrared (BIR) film is sensitive to the visible portion of the spectrum of light and extends into the near-infrared region of the spectrum. This USGS EROS film collection spans decades and includes a wide variety of films with different sensitivity, resolving power, granularity, and sharpness characteristics.īlack-and-white (BW) panchromatic film is sensitive to the full visible portion of the electromagnetic spectrum of light and captures images in tones of gray ranging from black to white. Single Frame Records include black-and-white, black-and-white infrared, natural color, and color infrared images. *The Alaska High-Altitude Photography Program was flown by these two organizations.