EXAMINING URBAN IMPERVIOUS SURFACE DISTRIBUTION & ITS DYNAMIC CHANGE IN HANGZHOU
Longwei Li, Dengsheng Lu, & Wenhui Kuang
Presentation By: Josiah Parry
SOME NEW TERMS
➤ Impervious Surface Area (ISA)
➤ Man-made surfaces that water cannot penetrate
➤ Albedo
➤ proportion of light reflected from a surface
➤ Modified Normalized Difference Water Index (MNDWI)
➤ NDVI for water
➤ QuickBird
➤ Sub-meter accuracy imaging.
HANGZHOU
➤ 5.8 million people 1990
➤ 8.8 million people 2013
➤ GDP increased 315 Billion in 23 years
➤ Mountainous in the West
➤ STUDY GOAL:
➤ Track expansion of city center.
➤ Focus on directions and densification
METHODS
➤ Create fractional images (breaking down pixels into smaller segments) why???
➤ Calculate MNDWI
➤ Use decision tree classification to produce High Albedo (bright) & Low Albedo images
➤ Produces bright, dark, & confused ISA
➤ Cluster confused ISA and manually determine if ISA
➤ Compare ISA from different time stamps
➤ Preform accuracy assessment
METHODS CONT.
➤ Calculate density (D = ISA / A) for each fraction
➤ Calculate difference in ISA
➤ Diff = ISA(t2) - ISA(t1) / t2 - t1
➤ Two types of increased ISA
➤ Densification and Expansion
➤ Calculate ISA amounts for each Elevation and Slope
➤ Why would they do this?
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