Data Dictionary: Walkway Schema Definitions from the walkway generator (sometimes called the sidewalk splitter) - OregonWalks/CR-Survey-Docs GitHub Wiki

  • a crosswalk is associated with one street segment
  • a crosswalk is at either the from end or the to end of a street segment
  • a crosswalk has its own from end and to end
  • a crosswalk connects two corners
  • a corner is defined by two street segments
  • the direction of crosswalks will be clockwise around a street node

Defining a corner from a crosswalk

It should not be necessary to do a join to get the information you need to define a corner from a crosswalk.  Chose one end or the other from the crosswalk (fm or to).  The corner at the chosen end is located by the first (fm) or last (to) point of the crosswalk polyline. The corner at the chosen end is defined by the street segment (street_seg) and the joining street segment (fm_join_ID or to_join_ID).  The bearing from the center of the intersection (as defined by the street centerlines) to the corner at the chosen end will be fm_bearing or to_bearing.  

Define bearing and the use of "bearing" in the walkway file.

There is no bearing for the walkway itself.  It is defined and I could calculate it and add a field but it could be misleading.  This is because the walkway generator places modeled corners at a certain distance from the center of the intersection.  Where real streets meet at a sharp angle the real corners may be far from the center of the intersection and that may cause the modeled crosswalk to be at a very different bearing than the real crosswalk.  The walkway generator places the corners along the bisector of the angle between the street centerlines.  The bearing to the modeled corner is likely to be close to the bearing to the real corner.  

fields (attributes) of a walkway shp file:

 

  • walk_type: crosswalk, midwalk (mid-block crossing), sidewalk, or st_walk (where single way makes sense - path or local street)
  • alignment: left or right for sidewalk or streetwalk, which end of the street segment (to or from) for crosswalk or midwalk
  • fm_end_type and to_end_type: corner or st_node (intersection center - where st_walks meet) street_seg: the ID of the associated street segment
  • to_end_ID and fm_end_ID: the ID of the associated street node at the to or from end of this walkway segment (both same ID for crosswalks and midwalks)
  • to_join_ID and fm_join_ID: the ID of the associated street segment that makes a corner at the to or from end of this walkway segment or -1 for st_walk
  • to_bearing and fm_bearing: the bearing from the associated street node (center of the intersection) to the corner at the to or from end of this walkway segment or the bearing of a st_walk as it leaves the intersection  

There are additional types for the case where st_walks meet sidewalk/crosswalks:

  • walk_type: fm_corner (connects a corner to a connect) or to_connect (connects a st_node to a connect) fm_end_type and to_end_type: connect (point like a corner created to connect st_walks to corners)
  • street_seg: -1 for all fm_corner walktypes
  • to_end_ID and fm_end_ID: (both same ID for fm_corners and to_connects)
  • to_bearing and fm_bearing: the bearing from the associated street node (center of the intersection) to the connect at the to or from end of this walkway or -1 for the from end of a to_connect    
  • The alignment of fm_corner and to_connect are fairly meaningless.
  • The to_join_ID and fm_join_ID of fm_corner and to_connect are fairly meaningless.