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

Satellite orbits (800km altitude) Landsat path: earthnow

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

http://www.lrdw.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/