How to field survey highway paths

tags

Scenario

One is out on the field and comes across a path that has not been mapped on OpenStreetMap. One chooses to create a survey field note.

At a later date, one processes the survey notes and realizes that one is having trouble georeferencing the details. Thus all the effort becomes useless in the betterment of OpenStreetMap.

Solution

With the utilization of the BFS field surveying heuristics1 one creates concrete reusable field notes.

BFS field surveying paths heuristic

The BFS field surveying paths heuristic is a schema for highway=path.

The field note utilizes the directionA value

1path <direction>

The value may be either a cardinal directionB (quick) or a degrees (slow) ranging from 0 to 359. (Image sourceC )

Compass presenting cardinal directions and degrees.
OsmAnd: field notes showing both degrees and cardinal direction overlayed on a radius compass that shows both degrees and cardinal direction.

Additional keywords

  • both: the highway continues straight across the intersection with the current highway.
  • stop: highway=stop exists at the head of the highway.
  • yield: highway=give_way exists at the head of the highway.
  • description of the path using characters like J, T, C, etc.

Evaluation of the heuristic

  1. The direction removes the ambiguity that may come from not precise note placement while in the field.
  2. The direction removes remembering what right/left means when reflecting back on the moment.
  3. The direction is not dependent on the screen orientation aligning with north.
  4. Using cardinal directions quickly surveys the path without requiring the phone to be orientated towards the path.
  5. Using degrees takes more time to survey compared to cardinal direction and may ease post-processing.
  6. The convention using degrees is to round to the nearest 10 or 45 (meaning NE=45°, SE=135°, SW=225°, NW=315°).

Post-processing

JOSM: post-processing path note with angle highlighted at the bottom of the app.

Post-processing within JOSM2 is simple since at the bottom of the app the angle information is presented. The way by default is highway=path unless additional information added in the note or can be deduced from aerial imagery.

NB fixme=* convention

  • If only mapping a short distance, then add fixme=continues? to give the potential to survey vel explore at a later date.
  • If estimating from aerial imagery, then add fixme=gps? to share that the way has been estimated and more concrete measurements are required.

References

  1. OpenStreetMap key direction=*, OpenStreetMap Wiki ↩︎
  2. Cardinal direction, Wikipedia ↩︎
  3. Compass with angles, OpenStreetMap Wiki ↩︎

  1. BFS field surveying heuristics cookbook, BFS Source↩︎

  2. JOSM editor, OpenStreetMap Wiki ↩︎