How Green is Our County? Street View Imagery Based High-Resolution and High-Accuracy Human Environment Vegetation Mapping

Measuring the amount of vegetation in a given area on a large scale has long been accomplished using satellite and aerial imaging systems. A primary limitation of these methods has been their ability to measure vegetation coverage accurately only at the top of the canopy, often neglecting green vegetation located beneath canopy cover. Measuring the amount of urban and suburban vegetation along a street network that is partially beneath the canopy has recently been introduced with the use of Google Street View (GSV) images, made accessible by the Google Street View Image API. Analyzing green vegetation through the use of GSV images can provide a comprehensive representation of the amount of green vegetation found within geographical regions of higher population density, and it facilitates an analysis performed at the street-level. In this presentation, we propose a fine-tuned color based image filtering and segmentation technique based on which we define and map an urban green environment index. We deployed this image processing method and, using GSV images as a high-resolution GIS data source, we computed and mapped the green index of Milwaukee County. This approach generates a high-resolution street level vegetation estimate that may prove valuable in urban planning and management, as well as for researchers investigating the correlation between environmental factors and human health outcomes