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Remote Sensing of Urban Landscapes and contributions of remote sensing to the Social Sciences. Urban-Suburban Land Use. Urban and suburban expansion almost 1/2 the Earth’s population lives in cities rapid expansion of urban centers and their peripheries
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Remote Sensing of Urban Landscapes and contributions of remote sensing to the Social Sciences
Urban-Suburban Land Use • Urban and suburban expansion • almost 1/2 the Earth’s population lives in cities • rapid expansion of urban centers and their peripheries • impacts on land cover, societal structure of the cities, population distribution, land use characteristics • interconnectivity of cites at large scales
Urban remote sensing • High spatial resolution data are needed • Temporal and spectral resolution are typically not a significant requirement for most applications • Ancillary data typically used (census data) • Can measure variables such as urban extent, housing density, structure type, urban vegetation cover, air quality, change detection
Temporal and spatial resolution requirements vary depending on applications: • short term (event-scale, sub-annual) vs. long term (interannual) • high spatial resolution (< 1m) vs. medium spatial resolution (15-30m) • (see Jensen Fig. 12-1)
High Spatial Resolution Sensors: • QuickBird (65cm B/W, 4m multispectral) • IKONOS (1m B/W, 4m multispectral) • SPOT (2.5m - 20m multispectral) • ASTER (15 -30m multispectral) • Landsat ETM+ (15m B/W, 4m multispectral)
Delineation of Urban Areas • Difficult to do because urban areas are diverse and complex • Boundaries between urban and suburban are not always clear • Lack of a consistent definition of “what is urban” • administrative boundaries • population density, etc.
Balitmore, MD: Well-developed city center Diffuse boundary between urban and natural environment Landsat TM multi-spectral image
Las Vegas, NV: Indistinct city center Distinct boundary between urban and natural environments Landsat TM multi-spectral image
Demographic/Socioeconomic Patterns • Census data lack spatial details and are infrequently updated (not globally available) • Remote sensing is useful for monitoring urban growth in developing countries • Need ancillary data plus repeat temporal coverage from remote sensing • Important to integrate physical and socioeconomic variables
Example Pozzi and Small (2002) produced a study of relationship between population density (from US census) and vegetation cover (from Landsat TM)
NYC Population Density NYC Vegetation Fraction (source: US Census) (source: Landsat TM) Linear inverse correlation between population and vegetation fraction
Urban Heat Island Monitoring • Project ATLANTA (Atlanta Land-use Analysis: Temperature and Air-quality) • Uses remote sensing to observe, measure, and monitor impacts of rapid urban growth
ATLAS Thermal Images of Atlanta, Georgia Atlanta - Daytime Image Atlanta - Nighttime Image
City Lights Imagery • Uses visible band of the Operational Linescan System (on board the DMSP satellite) • Useful for making global inventories of human settlements • Spatial resolution of 1km • Relationships between city lights and socioeconomic variables such as population density, economic activity, electric power consumption, etc.
Measurements of Pollution in the Troposphere (MOPITT) Carbon monoxide plumes from China 22 km spatial resolution, 640 km FOV
Disaster Monitoring • Volcanic eruptions • Tornados • Hurricanes • Oil spills • Earthquakes • War/terrorism • Floods
ASTER image of Maryland tornado path before after
AVHRR image of Hurricane Floyd September 1999
Bam, Iran Earthquake destruction IKONOS image from 12/27/2003
Quickbird image of explosion in Baghdad suburb 70 cm resolution
Flooding in Dresden, Germany August 22, 2002 QuickBird Satellite Image: 65 cm spatial resolution
Epidemiology • Cholera virus attaches to zooplankton (copepods) and phytoplankton. Plankton plumes emanating from the Ganges are being monitored • SST and plankton can be monitored in Bay of Bengal to track this • Hanta virus (carried by mice) correlates to changes in precipitation (El Nino) and vegetation cover, especially grasses • NDVI can be used to track these changes • Townshend et al. found that Ebola outbreaks corresponded to changes in land use and seasonal climate patterns
Landsat TM map of land cover near Kikwit, Zaire (location where Ebola outbreaks were first reported in 1995) pink=cleared areas green=jungle