Mapping Earth from Space Remote sensing and satellite images. Remote sensing developments from war

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1 Mapping Earth from Space Remote sensing and satellite images Geomatics includes all the following spatial technologies: a. Cartography "The art, science and technology of making maps" b. Geographic Information Systems (GIS) "Automated systems for the management, analysis, input and output of spatial data" c. Global Positioning Systems (GPS) "determination of ground locations using measurements from satellites" d. Surveying "science of determination of accurate coordinates of terrestrial locations" e. Photogrammetry "derivation of 2D or 3D locations from stereo pairs of aerial photography f. Remote Sensing "Acquisition of information about a planetary surface from a distance" Remote sensing developments from war US Civil War: Pigeons and kites First World War: photogrammetry Second world war: stereogrammetric mapping (with surplus planes) RADAR- RAdio Detection And Ranging Korean War: Infra-red photography Cold War: Satellite photography and imagery Gulf Wars: 3D imagery / google earth? 1

2 Topographic mapping , was completed using aerial photography incorporating stereo-photogrammetric techniques to map contours What is Remote Sensing? "Obtaining information about a planetary surface from a distance" The term first appeared ~1965 with the first satellite images (previously there were only aerial photographs) Also there was increasing use of nonvisible parts of the electro-magnetic spectrum, such as the Infrared Shopping centre - Phoenix, Arizona 2

3 Electro-magnetic Spectrum: "The range of wavelengths of energy" Energy (from the sun) radiates at wavelengths from very long (hundreds of metres) to very short (billionths of a metre: nanometres; and millionths of a metre: micrometres or 'microns') air photographs record energy 'reflected' at visible wavelengths ( nm) The visible portion of the EM spectrum contains the portion of the sun's radiation that we can see. Sample orthophoto 2010 Prince George 3

4 Infra-red (IR) photography IR was developed during the Korean War to distinguish between healthy vegetation and camouflage. Hence it was known as 'camouflage detection' film or 'false colour'. a yellow filter eliminates blue wavelengths (green displays as blue, red as green) infra-red wavelengths are shown in red, reflected by healthy vegetation Advantages of using Infra-Red wavelengths for mapping: Blue - the most susceptible to haze- is replaced (removed) Land-water distinctions are enhanced (but not urban features) Vegetation differences are enhanced, coniferous v deciduous etc.. Normal colour Infra -red 4

5 Scanners they create digital images (producing images NOT photographs) with layers of pixels (picture elements) - usually 8 bit = 256 values (0=dark to 255=bright) Close-up of pixels in a digital (scanned) image <- Prince George scanned image The near IR ( microns) records energy related to vegetation vigour (health), while the mid- IR ( microns) is related to (soil) moisture. Neither have anything to do with temperature Near-IR Mid-IR 5

6 Thermal Infrared (3-14 microns) This records longer wavelengths and is a measure of temperature as energy is emitted NOT reflected IR Microwave: 1mm 1 metre These wavelengths beyond the infra-red can see through' clouds, light rain, and snow, but there is a low amount of it ( why we use these wavelengths for communications). It is used to monitor sea pollution, global ice cover and atmospheric ozone. 6

7 Microwave: - RAdio Detection And Ranging (RADAR) is 'active' remote sensing at wavelengths of 1-30 cm (whereas most other remote sensing is 'passive': recording solar and terrestrial radiation). Passive Active RADAR was first developed before/during World War II for aircraft detection. As it is not affected by darkness or weather, it is especially useful in arctic regions for mapping ice; and tropical areas, which are consistently cloud covered as well as other areas often cloud covered, both temperate and tropical. It is also Microwave Ireland, 1991: Radar and Visible image 7

8 LiDAR = Light Detection And Ranging (Visible wavelengths).. is the other common form of active remote sensing It is commonly used to create high resolution DEMs (< 1 metre) e.g. PGmap elevation model Floodplain mapping Ground zero, New York Satellite Images for mapping This technology initially evolved from the Cold War space race. They range from low resolution (weather satellites) to very high.. capable of detecting objects <1 metre Especially useful for remote mapping Hurricane Katrina Landsat path: earthnow New Orleans, before and during Hurricane Katrina 8

9 Satellites have two types of orbit (GPS satellites include both types): 1. Geostationary: 36,000 km above equator, stay vertically above the same spot, rotates with earth - weather images, e.g. GOES (Geostat. Operational Env. Satellite) [Scanning enables the data to be transmitted back to earth from the satellites] 2. Sun-synchronous satellites: km altitude, orbit at ~ degree angle to the equator (= near polar): captures imagery approx. the same time each day (~ 10 11am) All satellites used for earth mapping are this type 9

10 Most satellite images are not photos but there are exceptions Millennium Island photographed by a crew member on the International Space Station This image was acquired with a Nikon D3 digital camera fitted with an 800 mm lens Spatial Resolution (pixel size) ~1 metre to 10 kilometres Low resolution (free) 1km - 10km (international) small scale /mostly weather Medium resolution (free) 100m -1km (national) - suitable for ~ 1:250,000 High resolution (some free) m (regional) - suitable for 1:50,000-1:100,000 Very High resolution (costs $) 1-10 metres (Local) - suitable for > 1:50,000 10

11 Small scale satellite images (10km) Low resolution imagery (~10km pixels) Daily sea surface temperatures using Microwave wavelengths cloud free 11

12 Medium resolution: MODIS 500m 1km High resolution: Landsat (since 1972) Satellites 1,2,3 had a Multi- Spectral Sensor (MSS) with a pixel size 80 metres in resolution. First Landsat image: San Francisco Reservoirs in Quebec

13 Thematic Mapper (TM): present Landsat satellites 4 and 5 had higher resolution (30 metres) Thematic Mapper Enhanced Thematic Mapper (ETM+) (Landsat 7) This is the basis of Google maps and Google Earth coverage; data was free since Landsat 8 launched in 2013 Google maps Visible image like an air photo BC LRDW imap Including Near-IR and mid-ir 13

14 1985 Mapping change / updating: Berg Lake and Robson Glacier

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16 Download from earthexplorer.usgs.gov High resolution: Landsat-like SPOT (France) 1986 (20m) receiving station: University of Lethbridge,

17 ASTER (with DEM) Longyearbyen is located on Spitsbergen, the largest island of the Svalbard archipelago, part of Norway. It is the world s northernmost town with over 1000 people - and world s northernmost university. 17

18 Radar image, Vancouver RADARSAT 2 Radarsat 1-2 are the only Canadian satellite systems in space for mapping Radarsat Radarsat 2: > John MacDonald, founder MacDonald-Dettwiler Associates, Richmond, BC Chancellor, UNBC Very high resolution satellites First corporate satellites > Ikonos: 1m image resolution Dubai Whistler,

19 there are now very high resolution satellites Others include: -Worldview 50cm - GeoEye 41cm Quickbird (2001) 60cm pixels its so big you can see it from space : 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 90kg 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.' 19