Land Use Land Cover Change in the Phoenix

Land Use / Land Cover Change in the Phoenix Metropolitan Area 1984 - 2011 Lori Krider & Melinda Kernik 1984 2011

Introduction • Why Phoenix? o One of 10 fastest growing cities from 1990 - 2000 (Perry & Mackun, 2001) o Arid regions with high population are water stressed o Water use is reflected by how the land is used and managed o How is the landscape changing and how does this effect water use?

Objective • Use remote sensing software to assess land use / land cover change in Phoenix from 1984 – 2011 o Expect to see dramatic changes due to rapid population growth § Increase in urban and suburban areas (sprawl) § Increase in cultivated areas on edges of metropolitan area § Decrease in natural vegetation

Objective • Study Area o Phoenix-Mesa Metropolitan Area § South-central Arizona § 16, 200 km 2 § Phoenix, Mesa, Tempe, Chandler, Gilbert, Scottsdale, Glendale, Sun City, Peoria, and Avondale Google Maps

Preparation • Tools: ERDAS IMAGINE 2011, USGS GLOVIS, Arc. GIS 10, Google Maps. TM and Google Earth. TM • Materials: Landsat TM images from 1984 and 2011 (two from each year, 30 m res. , 7 bands, June), 2006 NLCD • Pre-classification processing o o o Stack bands, mosaic and crop images for each year View NLCD Unsupervised classification (5, 6 & 7 classes)

Analysis • Supervised classification o Anderson Hierarchical Classification (levels 1 and 2) § Altered, unaltered, developed and water § Altered § Human-assisted: healthy and stressed crops, golf courses § Uncultivated: fields not reflecting in IR § Unaltered § Natural: upland scrub/shrub (not in IR) § Hydrophillic vegetation: depressional vegetation often associated with water (in IR) § Water: lakes, rivers and large golf course water hazards § Developed § suburban (dwellings) & urban/roads (commercial/industrial)

Analysis • Training Areas o o 15 - 45 Why? § Errors in first run with less training areas § Combination of smaller category classes (i. e. healthy crop + stressed crop) § Reduce confusion and capture variety • Change Detection o o Thematic: 1984 -> 2011 Difference § to identify areas of significant change and overall patterns § 10, 20, and 30% thresholds

Post-classification • Accuracy Assessment o o stratified random same mosaics as reference o o switched "trainers" 140 reference points (20 per class) § added Google Maps. TM for 2011 http: //www. cartoonstock. com/directory/b/bad_appraisal. as

1984 2011

Thematic Change Detection Purple: Change to Suburban Light Blue: Change to Urban

1984

2011

Purple = changed to Suburban Blue = changed to Urban

Green = more than 20% increase in NIR Blue = more than 20% decrease in NIR

Thematic Change Detection

1984 Limitations! 2011

Accuracy Assessment

For future classifications: • Clip to the smallest possible boundaries – More ontological classes = more classification confusion • Complications using 30 m resolution images for reference data and the same image. • Use this technique, to generate water infrastructure policy for Phoenix …probably not

References 1. Perry, M. J. & P. J. Mackun. Population Change and Distribution 1990 - 2000: Census 2000 Brief. April 2011. United States Census Bureau. 12 Nov. 2011. <http: //www. census. gov/prod/2011 pubs/c 2 kbr 01 -2. pdf>.