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REMOTE SENSING and AERIAL PHOTOGRAPHY
Roger Wheate
NREM100 Fall 2010
Remote Sensing
• information about an object by a recording device not in contact with the object
• cameras, lasers, scanners, radar systems, Lidar
• the term did not exist before satellites (1960s) increased the scope of aerial surveys with digital scanning
Remote Sensing
• 1910s: First (wartime) aerial photography
• 1940s: aerial photography programs
• 1960s: first satellites: Espionage, weather,
communications
• 1970s: Digital imagery for earth mapping
• 2000s: free web images
Early aerial photography (before planes):
balloons, pigeons and mountain tops
Oblique photos from mountain peaks: Banff
Oblique photography
Post-1945: Panchromatic aerial photograph: Iqualuit
Aerial Photography • Aerial photography = two sciences:
– Photogrammetry (=precise locations and heights)– Air photo interpretation (=feature identification)
• Advantages over ground surveying– Cost and time-convenience– Historical record
Aerial Photography• Flightlines
• Overlap
• Corrected and mosaiced
• Type: Pan, Colour, IR
Air Photo Interpretation
• Tone / colour• Texture• Shape• Pattern• Size• Shadows• Context
Colour photography – 2x as expensive
Infra-red photography – 3x as expensive
1:50,000 NTS maps
(from photos)
(1:20,000 BC maps/data)
PG 93G015
Photos 1996Printed 2000Roads updated, other 1982
Reprinted 2010Roads updatedOthers still 1982
BC aerial photography 2007
Digital aerial photography
www.terrasaurus.ca
Orthophotos as digital map layers: 1993, 2003, 2006 http://pgmap.princegeorge.ca/
BC ‘imap’: http://lrdw.ca
Applications
• All natural resources disciplines– Navigation and mapping– Forest inventory– Geologic surveys– Natural hazards– Land use change– Wildlife habitat assessment
Photos – 1:15,000 = 4km x 4 km; 1:40,000 = 10km x 10km
Satellite images: 60 x 60 km ; 185 x 185km; 500 x 500 km
Merge of satellite image and orthophoto
• 1960s – weather satellites• 1972 – Landsat 1 • 1982 – Landsat 4
• 1990s – more earth-resources satellites
• 1999 – Landsat 7 (copyright removed)
• 2000 – high resolution corporate satellites
• 2005 Web applications
Remote sensing - Satellite imagery
Port Renfrew, Vancouver IslandPre 1984 cutblocks in pink, 1984-91 in blue
Landsat image – Bowron Lakes 30 metre resolution
Vegetation Information and the Electromagnetic Spectrum
• Visible visible characteristics (RGB)
• Near IR vegetation vigour / health
• Mid IR vegetation and soil moisture
• Thermal IR temperature / heat
• Microwave/Radar texture e.g. high for forest
2003
2007
High resolution corporate satellites: Geoeye (50cm res.)
Cypress Bowl – Feb 19, 2010
Applications – remote sensing
• Geologic – faults, deposits, exploration• Vegetation – forestry, agriculture, ecology• Urban - land use, growth• Geography – regional and local studies
• ASTER: http://asterweb.jpl.nasa.gov/
• Ikonos: http://www.satimagingcorp.com/gallery-ikonos.html
• Quickbird: http://www.satimagingcorp.com/gallery-quickbird.html
• Geoeye: http://www.geoeye.com/CorpSite/gallery/Default.aspx
• BC mosaics: http://www.lrdw.ca
• Google maps: http://maps.google.ca
NASA – images of the day http://earthobservatory.nasa.gov/IOTD/
Google Earth (since 2005): aerial photography and satellite images
The giant dog you can see from space
Monday, June 9, 2008 BORIS the bull mastiff is so big that he can be seen lounging in his favourite position in the garden - from space. The 89kg dog has been captured on Google Earth's satellite images. His owners noticed an enormous brown blob on the image of their front garden and were stunned to discover it was their pet. 'He was in his favourite place,' said Fran Milner, from Bournemouth. We knew he was big but didn't think he was big enough to be seen from space.'
Google Earth: aerial photography and satellite images / mashups
Filmaps
http://www.thewildernessdowntown.com/