Return the bearing of a polygon edge based on selection using Arcade

Jake_S

Greetings folks,

Looking to be able to return the bearing of the side of a polygon based on a interaction.

I have a carto points feature class that I want to populate its F_ANGLE field with the bearing of the side in which intersects with a polygon. We use that bearing to change the symbology rotation. Any help would be great. 

The image below shows a polygon and a point with symblogy interacting. I'd like to get the bearing of that intersection

I have got this working for an intersection of a line feature but not a polygon (image below). 

Code for the intersection of lines is below, replacing the feature with a polygon does not work. Looking for someone with a bit more coding knowledge for some help

 

 

 

 

 

 

 

var LinesFC = Intersects(FeatureSetByName($datastore, "Lines", ['objectid', ''], false), $feature)
if (Count(LinesFC) > 0) {
    var line = first(LinesFC)
    var geom = Geometry(line)
    var pt0 = geom.paths[0][0]
    var brg = Bearing(pt0, Geometry($feature))
    if (brg > 90 && brg <= 360) {
        return (450 - brg)
    } 
    return (90 - brg)
}
return null

 

 

 

 

 

 

 

Thanks in advanced.

-JS

JohannesLindner

 

var PolyFC =Intersects(FeatureSetByName($datastore, "gewaesserkataster_sde.GWK_SDE_ADMIN.poly"), $feature)

// return early if no intersecting polygon is found
// doing it this way saves you from indenting everything in your if block
if(PolyFC == null || Count(PolyFC) == 0) {
  return null
}

// lines have the "paths" attribute, for polygons that's "rings"
var poly = First(PolyFC)
var geom = Geometry(poly)
var pt0 = geom.rings[0][0]
var brg = Bearing(pt0, Geometry($feature))
if (brg > 90 && brg <= 360) {
  return (450 - brg)
} 
return (90 - brg)

// if that works for you, cool.
// I got really inconsistent results when testing this on irregular polygons, though, 
// so I'd go with something like this:

var poly = First(PolyFC)
var vertices = Geometry(poly).rings[0]
var sr = Geometry(poly).spatialReference
// loop through the vertices
for(var r=0; r<Count(vertices)-1; r++) {
  // create a line segment between 2 adjacent vertices
  var p0 = vertices[r]
  var p1 = vertices[r+1]
  var line = Polyline({"paths": [[ [p0.x, p0.y], [p1.x, p1.y] ]], "spatialReference": sr})
  // do nothing if $feature doesn't intersect that line segment
  if(Disjoint($feature, line)) {
    continue
  }
  // return the bearing of the line segment
  var brg = Bearing(p0, p1)
  if (brg > 90 && brg <= 360) {
    return (450 - brg)
  } 
  return (90 - brg)
}
// if you land here, the feature intersects a polygon, but none of its edges
return null