the study area was created from the PA municipalities shapefile by selecting Lancaster and York County municipalities adjacent to the Susquehanna river and saving this as a feature class; all other input data was clipped to this study area

the currently preserved parcel data provided by the counties (see A) was merged with additional parcels under management by the Lancaster Conservancy (see B) as nature preserves

the merged preserved parcels above were 'erased' from parcel data supplied by the counties (see C), resulting in an 'unpreserved parcels' feature class

the observation point features referenced in 'Required data' were used as input to an ArcGIS server/cloud based viewshed calculation, using elevation data resident on the server and the separate viewsheds were merged and dissolved

the viewshed feature class resulting from above (see D) was used to 'clip' from 'unpreserved parcels' only those parcels within the viewshed

land use raster data for York and Lancaster county, obtained from the Chesapeake Conservancy, was merged and converted to vector data, and selection was used to create a feature representing 'forest' land use (see E)

though not used in the parcel selection model here, separate features were created via land use selection for 'pasture' land use, and multiple wetland land use codes were combined into a 'wetlands' category

by 'summarizing' the amount of forest within each parcel, and then 'selecting', the model can select only those parcels with a given minimum area and percentage of forest -- these minimum values are specified by the parameters (in blue -- see G)

a select by location tool was used to further restrict parcel selection to those parcels adjacent to already preserved parcels -- this represents our final selection of parcels for preservation

a 'flow line' feature class (see F), representing tributaries of the Susquehanna river, was used with the above parcel preservation candidates as input to a 'summarize within' tool, which replicates the input parcel data and adds a field with the length of streams within the parcel boundary

the 'summarize within' tool can also be used to measure how much of any land use category is within any parcel

parcels selected for preservation were then classed in one of three color coded categories based on the contained stream length for the final resulting map