30 Oct Examining Vegetation Changes Through Near-Infrared Imagery
The Map of the Week for October 30th examines the balance of structures and vegetation around the University of Utah campus by comparing past vegetation areas to those found today through the use of GIS and near-infrared imagery. #MapMonday
Developing a vegetation analysis begins by converting a 4-band or higher satellite image into a near-infrared visualization, displaying reflected light as well as the red light absorbed by plants. The near-infrared visualization is converted into a Normalized Difference Vegetation Index (NDVI) that quantifies healthy vegetation and returns a classification of high and low vegetation on a scale of -1 to 1. Color ramps allow these values to be visualized on the map, with high vegetation areas appearing darker green and low vegetation areas appearing darker red. By interactively overlaying this analysis on a present-day satellite image using a swipe comparison tool, evidence of current and past vegetation changes can easily be visualized.
The vegetation analysis for the University of Utah campus for the past 3-years depicts a consistent balance of vegetation and structural areas. Moderate changes can be found in the centralized portions of campus due to construction and development while exterior portions have remained consistent over time.
About Map of the Weeks from GIS Services:
Throughout the semester, GIS Services will continue releasing bi-weekly maps on a variety of topics for the purpose of demonstrating ideas and uses for incorporating geospatial technology into research and projects you are developing. To view our collection of maps, projects or to learn about the geospatial services offered through the Marriott Library, please visit the GIS Services website @ www.lib.utah.edu/services/geospatial
Justin Sorensen | GIS Specialist
Creativity & Innovation Services / GIS Services