Urban Development changes detected by NDVI in Rossford, Perrysburg, Perrysburg Village, Ohio.

Christina Stevens

Geography and Planning, University of Toledo, 2801 W. Bancroft, Toledo, Ohio, 43606

This study identifies changes in land development by detecting loss of vegetation to new growth in residential, commercial, industrial areas. The Normalized Difference Vegetation Index (NDVI) is used to measure density of plant growth over an area of space. Increasing development in Rossford, Perrysburg, and Perrysburg Village has prompted this study to be aware of how the cities are growing. NDVI was measured for all images. The NDVI difference between the 09-09-2002 and 05-04-2002 images were calculated to show the reduction in vegetation. The NDVI difference between the 09-09-2002 and 05-04-2002 images were calculated to justify winter wheat fields. The high to low change NDVI gray scale images were transformed to brown-green (high to low change) color scale through ArcMap. In situ analysis, ground truthing, pictures were taken by random sampling at eleven sites. The final map accurately displayed green polygons to show little or no change in vegetation, and brown polygons to represent the loss of farm land to new urban development.

Introduction

As a resident of Perrysburg Village, I began to notice incredible losses of farm land within the area and the surrounding cities Perrysburg and Rossford. Within the past two years several shopping areas, warehouses, and residential areas have been developed. The danger of pocket growth for urban planning caused me to be curious of how these cities were developing. The table below shows the total population growth from 1990 to 2000. I also added persons greater than 18. This part of the population would have the ability to purchase a home or have separate living quarters.

Total Population Growth	1990		2000		Percentage of Change
City	Total	>18 years	Total	>18 years	Total	>18 years
Perrysburg	12,551	9,083	16,945	12,037	35%	33%
Perrysburg Village	13,176	10,178	13,613	9,973	3%	-2%
Rossford	5,861	4,440	6,406	4,780	9%	8%

The Normalized Difference Vegetation Index (NDVI) is used to measure density of plant growth over an area of space. When you subtract an image from a year to a later year, NDVI identifies areas where plant growth no longer exists. It was very important to incorporate images from the same time period because, absorption and reflection of the sunlight is measured by wavelength readings. NDVI measures chlorophyll in the plant leaves, which absorb visible light (from 0.4 to 0.7 µm) for the activity of photosynthesis. The cell structure of the leaves, on the other hand, strongly reflects near-infrared light (from 0.7 to 1.1 µm). The more leaves a plant has, the more these wavelengths of light are affected, respectively. A zero means no vegetation and close to +1 (0.8 - 0.9) indicates the highest possible density of green leaves. Images from the dates 08-16-1999 and 09-09-2002 were used to identify change in the area. The 05-04-2002 image was used to justify winter wheat farms.

Data Used

Stacked subsetted Landsat 7 (2031) images.

NDVI was measured for all images. All of the NDVI images were transformed from gray scale to a brown to green (high to low) scale for better viewing.

08-16-1999 09-09-2002 05-04-2002

NDVI Difference Images

Brown color represents a high change in NDVI, whereas, the green shows a low change in NDVI. The NDVI values are indicated on each individual map.

Equation

Equation

Difference of the difference image

Photographs

Site 1

Route 65 East of 475

Site 2
Route 65 East of 475

Site 3
Perrysburg High School

View in the opposite direction

Site 4
Eckel Junction

Site 5
Residential View – once was a field

Site 6
Residential Development

Site 7
Commercial Development

Site 8
Commercial Development

Site 8
opposite view

Site 9
Road Development

Same location – Baseball training camp

Site 10
Rossford Amphitheatre

Site 11
Light Industrial

Results

histogram table from proposal 1

Final map for Site Locations

Conclusion / Future Direction

This project will be beneficial for future urban planning discussions. The results of this study shows specifically how the cities are developing. At this moment, the three cities are growing in "pockets." With the area of land available, and the speed of development the cities are growing, it would imperative to insist on sustainable growth. This could reduce unavoidable costs. This would also enhance long term benefits for future generations. Smart Growth concepts should be addressed. Mixed-use zoning, pedestrian friendly walkways, and value of green space will promote organized growth. Also, PerrysburgTownship, a bedroom community, does not have a town center or community center. The town center could be located around the proximity of the police station.

Additional research would involve GIS integration. GIS would be an excellent tool for future analysis to integrate data from the US Census Bureau.

Bibliography

http://earthobservatory.nasa.gov/library

· Weier, John, and Herring, David. “Measuring Vegetation (ndvi & evi).” Earth Observatory. http://earthobservatory.nasa.gov/library /measuringvegetation

· “Urban Climatology and Air Control. Remote Sensing, Heat Island http://www.ghcc.msfc.nasa.gov/urban/urban_remote_sensing.html

· Weier, john. “Urbanization’s Aftermath.” Earth Observatory. July 15, 2002.

US Census Bureau