Web Mapping, Spatial Analysis
The embedded web app was created as part of the Philly Tree Plan to help Philadelphia establish a ten year plan for the planting and care of our urban forest, guided by values of environmental justice, community engagement and sustainability.
It was created through a collaboration between the Pennsylvania Horticultural Society (PHS) and Philadelphia Parks & Recreation to guide individuals and organizations in our collective efforts to create a greener and more equitable city.
Street trees play a critical role in cleaning pollutants from our air and water, cooling our homes, reducing our stress levels and creating wildlife habitat. This map is meant to highlight the streets and neighborhoods that are most in need of additional street tree plantings based on a variety of factors.
The prioritization layer was created by determining the criteria and weights that would decide which streets are most in need of additional street trees, rasterizing all input layers to only pick up values from the input layers that are 50 feet around each street, standarizing each rasterized input layer, and using the Weighted Sum tool in ArcGIS Pro to specify each input layer's weights and highlight the streets that have the highest prioritization scores for each of the 13 input layers. These areas were then vectorized and joined to the Philadelphia street centerline layer.
The suitability layer was created by first determining what should not be considered plantable space according to local tree planting guidelines; this includes existing tree canopy, areas that are 15 feet from fire hydrants, areas that are 3 feet from buildings, etc. A union operation was used to combine all exclusionary and inclusionary layers (the impervious and pervious area around each street) into one layer from which exclusionary features could be removed. The area of inclusionary layers per street centerine segment area (50 feet around each centerline) was then calculated as a percentage and joined to the street centerline layer. This analysis also included estimating sidewalk segment width; this methodology is detailed here.
More information for the street tree priority and opportunity layers can be found here.