Remote Sensing Week 5
Remote Sensing Week 5 GEOG 2107
Popular in Intro to Remote Sensing
verified elite notetaker
Popular in Geography
This 3 page Class Notes was uploaded by Ivana Szwejkowski on Wednesday September 28, 2016. The Class Notes belongs to GEOG 2107 at George Washington University taught by Engstrom, R in Fall 2015. Since its upload, it has received 3 views. For similar materials see Intro to Remote Sensing in Geography at George Washington University.
Reviews for Remote Sensing Week 5
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/28/16
Remote Sensing Week 5 rd Exam 1 is October 3 Air Photo Geometry and Stereo Viewing continued Orthographic Projection – map; true position Central Projection- vertical air photo - Object shifted from true position- displaced - Nadir point- only true position - Away from nadir- camera increasingly sees object sides Relief - Objects will tend to lean outward, be radially displaced - The greater the object is from the principle point, the greater the radial displacement Relief displacement: radial distance between an objects image position and its true plan (horizontal) position due to differences in object relief -used to distinguish height Cause: All objects on a vertical air photo are position as though viewed from the same point Camera increasingly sees the side of an object further away from its nadir- objects appear to lean Relief displacement- Magnitude - Object height, distance from nadir point, and H - Displacement at nadir = 0 - Points higher than datum- lean outward - Points below datum- lean inward Photogrammetry: art and science of making accurate measurements by means of aerial photography Calculate object height (2 ways) 1. Based on relief displacement D, Distance from principle point (r) & height above ground level (H) 2. Based on height from shadow length: Scale of imagery is known, shadow must be cast from true top of object, shadow must fall on open level ground undistorted Based on shadow length (L) times tan(a) Stereoscopic Veiwing -Provides 3 dimension to air photo interpretation - identify 3-D form of an object -Stereopairs: overlapping vertical photographs, -Stereoscopes: used to create synthetic visual response by forcing each eye to look at different views Stereoscopic alignment: alignment of air photos - Lines up along the flight line Parallax- length of air base- distance of aerial photo source taken, difference of eyes, height of object, H0= (H-h)(dp/ P+dp) Platforms -Ground based: hand held/ cranes -Airborne: Stationary; captive/tethered balloons Aircraft: manned and unmanned -Satellite Airborne: Free floating balloons, Blimps/ dirigibles Helicopters: can pin-point locations, lack stability Low altitude aircraft: operate below 20,000 feet Most widely used are single engine or light twin engine Imagery can be obtained by shooting out the window or placing camera mount on window High altitude Aircraft -Above 20,000 feet -stable -Large areas, smaller scale -Includes jet aircraft with good rate of climb, maximum speed Advantages of aircraft -easy to mobilize, time of coverage can be controlled, control platform variables such as altitude Disadvantages -motion blurring, drift off course, expensive Aerial Cameras- frame camera - High geometric image quality - Characteristics include: - Film rolls (100-500 ft in length) - Large film format (9 in X 9 in, 23 cm X 23 cm) - Low f/stop – Fast shutter speed - Film- can only be used to look at 3 portions of the electromagnetic spectrum - 2 major(true color, color infrared) National Aerial Photography Program - Standardized set of cloud-free aerial photography Photographic Concepts - Exposure: total amount of light striking film and/or charge coupled devices (CCD) - Film CCD exposure primarily function of scene brightness- aperture - Diameter of lens opening - Exposure time- shutter speed Range for spacecraft is determined by orbit which is fixed in altitude and inclination; sun synchronous, and geostationary.
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'