Fig. 4From: The Health and economic effects of light rail lines: design, methods, and protocol for a natural experimentBuffer comparison showing the “sausage” or balloon buffer and the same buffer combined with the interior or island polygons. Image A is the buffer form used to calculate all built environment variables including counts and intersecting features. The area derived from the Image B form was used as the denominator for all density measures.©2019 Urban Design 4 Health, IncBack to article page