- Air Photos
- Review
- Remote Sensing
- definition
- acquiring information about objects
- without coming into contact
- instead use reflected EMR ("sun's energy") or our own energy source
- e.g. eye sight, camera/detector (images: photos, satellite, radar, LiDAR, etc)
- energy source (signal source)
- camera/ detector location
- spectral range of images
-
- = "energy" that travels in the form of a wave emitted by the sun (stars)
- Activities (uses)
- photogrammetry
- photo interpretation
- orienteering
-
- oblique
- vertical (<3 degrees)
- Lights! Camera! Action!
- Air photo geometry & scale
- perspective
- scale
-
- flying altitude is above MSL, usu. in feet
- H is flying height above the ground
- the difference is elevation, thus ...
- H + elev = flying alt.
-
- if elev varies in a photo ...
- ... then H varies ...
- ... and scale varies too
- Can also just average the H to get ave scale
- calculation (ratios)
- photo / RW (= photo dist. / real world dist.)
- f / H (focal length / height of camera above ground)
-
- H
- dist. from lens to ground
- greater height, the smaller the scale
- f
- dist. from lens to negative
- greater the f, the larger the scale
-
- questions
- photo no. gives focal length (30BCC3452-121) ... f = 30cm
- handy conversions: 1 ft = 30.5cm, 1 m = 3.28ft
- scale? photo = 4.4 cm, RW = 880 m
- scale @ sea shore? 30BCC3452-121, A = 12,328 ft
- scale @ cabin? same as above but ... elev = 100 m
- H(ft)? scale 1:24,000, f = 6"
- E(m)? alt.= 23,000ft, f= 305mm, scale 1: 20,000
