Download Assignment 6

Adrian Dahlin
11/11/10
Intro to GIS - Parmenter
Assignment 6: Initial Project Description and Data Documentation
A.
B.
Greenspace/blackspace ratio.
Sources
1. Pang, W.T., Fok, H.S., Bâki Iz, H. Mapping impervious surface areas from GIS
planimetric data (2008) Survey Review, 40 (308), pp. 108-115.
• Pang et al. come up with a method of mapping impervious surfaces in Hong Kong.
They first define impervious surface as “any material, natural or man-made that
prevents the infiltration of water into the soil” and cite its impact on biodiversity, air
quality, temperature, noise pollution, wildlife habitat, water, and urban planning.
The article then focuses on discussing sources of error in the making of ISA
(impervious surface area) maps.
• One interesting point: in less dense areas where they have no data for the space
between densely packed buildings, they assume that the area in between buildings is
impervious. This is supported by their undocumented observation that in Hong
Kong these areas do indeed tend to be impervious.
• They use a sample of actual observation sites to determine the accuracy of their GIS
data.
2. M. Falkenmark, & J. Rockström “The New Blue and Green Water Paradigm: Breaking
New Ground for Water Resources Planning and Management”
• Falkenmark and Rockstrom differential between the flow of surface and ground
water (blue water) and moisture in unsaturated soil (green water). This article
spends a lot of its focus on agriculture - the water that feeds agriculture is
differentiated as green water. Agriculture decreases the availability of blue water
for ecosystem and human use.
• The authors discuss balancing green and blue water.
3. Goetz, Wright, Smith, Zinecker, and Schaub. “IKONOS imagery for resource
management: Tree cover, impervious surfaces, and riparian buffer analyses in the midAtlantic region”
• This study uses IKONOS satellite imagery to look at impervious surface and tree
cover. They find that this method yields comparably accurate results to manual
aerial photography.
• They use the imagery to assess the health of streams based on the percentage of
their watersheds that are covered by impervious surface and tree cover.
4. Berke, MacDonald, White, Holmes, Oury, Line, and Ryznar. “Greening development
to protect watersheds: Does new urbanism make a difference?”
• The authors attempt to answer the question of whether or not modern “green”
development practices make a difference in protecting sensitive watersheds. They
compare 50 pairs of new- and convention-style developments in the United States.
• They find that more dense development creates less impervious surface and allows
for more deliberate protections of vulnerable habitats. New-style developments
were more likely to restore damaged stream ecosystems.
C.
D.
• This paper affirms the significance of a greenspace-blackspace study. Reduced
blackspace is in fact a goal we should be seeking.
METHODS:
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I will split the land use layer into eight categories, with a focus on six of these.
The categories are natural green space (dark green), semi-natural green space
(medium green), mediocre green space (light green), 3 levels of impervious land
(light gray, medium gray, and dark gray), beach (because it doesn’t really fit into
green or black space, and it can be natural or man-made), and water.
◦
I will assign values to the six main categories: +3 for dark green, +2 for medium
green, +1 for light green, 0 for beach, -1 for light gray, -2 for medium gray, and -3
for dark gray. I will use the geometry calculator to find the acreage of each
category, and then calculate the values for each category and the overall number
given to the city or region.
◦
I will focus on the Boston area, providing detailed maps to show the greenspace
and blackspace in this area. I will also use the system to calculate the score for
several other cities around the US. I may then see if the ranking between these
cities lines up with other comparisons of cities’ sustainability (such as Kent
Portney’s rankings).
◦
See final paragraph for some comments on possible alternative methods.
Data Layers
M:\
State
MA
MassGIS
Physical_Resources
LandUse2005
M:\
State
MA
MassGIS
Physical_Resources
Hydro_poly
The hydro layer is only for visuals on the maps.
Accuracy – The Land Use layer has a 1-acre MMU. I don’t know how this corresponds to linear
accuracy. Something like 10 meters would be good. However, I care more about the relative
accuracy of the areas of each Land Use category than I do about the accuracy of the layer vis-àvis reality. In the project itself I will not be comparing the layers I use with reality.
I’m still wondering if land use is in fact the best way for me to calculate the greenspaceblackspace ratio. I may need to use more accurate data that does not come from one layer. For
instance, I could find an accurate open space layer for Massachusetts (or just the Boston area)
and use another layer that illustrates black space down to the building level. I could construct
this more like a nolli map with green space and roads included. I think that this method would
inevitably leave some white space, however. A big benefit to using land use is that it is a
comprehensive layer. My project would be best if it incorporated information on the whole land.