Write-up

Swinburne Connection
Line Name   surface  routes  total miles  gap  off_road  on_road  closed  unknown  other   
map Hot Metal to Swinburne Road  Trail Open Asphalt  swinburne,pghParks  0.3741    0.3741            
map through the Swinburne Parking Lot  Road Low Volume Asphalt  swinburne,pghParks  0.0547      0.0547          
map Swinburne Parking Lot to 2nd Ave  Trail Open Protected Bike Lane  swinburne,pghParks  0.0671    0.0671            
map 2nd Ave to soccer field parking  Trail Open Protected Bike Lane  swinburne,pghParks  0.453    0.4530            
map Soccer Field parking to Panther Hollow Lake  Trail Open Asphalt  swinburne,pghParks  0.5331    0.5331            
           
Swinburne Connection  total for Trail    1.482    1.4273  0.0547          
           

Trail Lines are typically entered by tracing satellite imagery to extract latitude/longitude coordinates. The accuracy of these coordinates changes depending on the source of the photo and the precision of placement. I have seem satellite edges mismatched on the order 55 feet. Line work is sometimes extracted from the Open Street Map Project and from Strava heat maps.
>Milepost Known milepost (are placed on the map when they are visible in the satellite image or can be located via to visible features in the image. Other miles posts are extrapolated using calculations along the rail line. Note Railroads have also been known to realign trackage and not move existing mileage markers, only making an annotation on their paper maps.
Distances Above are based on the google map distance between two points along the line work.