[Arcade] Get z-Value from intersecting feature

StefanAngerer — Fri, 11 Nov 2022 09:38:43 GMT

Hi there,

I am yet again standing infront of a problem :') I am currently trying to edit the geometry of $feature by giving it the z-value of an intersecting feature. For this to work I created this code snippet:

var lines = FeatureSetByName($map, "linefeature", ["globalId"], false)

var intersectingLines = Intersects(lines, $feature)
var lines = count(intersectingLines)

if(lines == 1){
var intersectingLine = First(intersectingLines)
var newGeo = Point({
"x": Geometry($feature).x,
"y": Geometry($feature).y,
"z": Geometry(intersectingLine).z,
"spatialReference": Geometry($feature).spatialReference
})
SetGeometry($feature, newGeo)
return true
} else {
return true
}

So far so good, but somehow it won't work. Any Ideas what could be the problem?

Thanks!

Stefan

Re: [Arcade] Get z-Value from intersecting feature

StefanAngerer — Fri, 11 Nov 2022 10:58:35 GMT

I managed to slove it myself. It was a problem with the result statement. This is the snippet that worked for me:

var lines = FeatureSetByName($map, "linefeature", ["globalId"], false)

var intersectingLines = Intersects(lines, $feature)
var lines = count(intersectingLines)

if(lines == 1){
var intersectingLine = First(intersectingLines)
var newGeo = Point({
"x": Geometry($feature).x,
"y": Geometry($feature).y,
"z": Geometry(intersectingLine).z,
"spatialReference": Geometry($feature).spatialReference
})
return { "result": { "geometry": newGeo } };
} else {
return true
}

Re: [Arcade] Get z-Value from intersecting feature

MikeMillerGIS — Fri, 11 Nov 2022 11:15:23 GMT

It is fairly more complex than that. I have not tested this at all, but this should get you started.

// How man decimals to round coordinates to check if identical // GCS should use a large value, such as 9 // PCS should use a value such as 4 var compare_coordinate_round_value = 2; // When walking the line to split, a line is created between pairs of vertex // this value is the distance ito determine if the created point is on that line // GCS should use a small value, such as 0.0001 // PCS should use a larger value, such as 0.1 var point_on_line_tol = 0.1; function get_z_at_location(line_geometry, point_geometry) { var point_coord = null; if (TypeOf(line_geometry) == 'Dictionary') { line_shape = line_geometry; } else { line_shape = Dictionary(Text(line_geometry)); } point_coord = [point_geometry.X, point_geometry.Y]; var line_path = line_shape['paths']; // If the point is at the start or end if (compare_coordinate(point_coord[0],point_coord[1], line_path[0][0][0], line_path[0][0][1])) { return line_path[0][0][2]; } if (compare_coordinate(point_coord[0],point_coord[1], line_path[-1][-1][0],line_path[-1][1])) { return line_path[-1][-1][2]; } var min_distance = point_on_line_tol * 2; var z_value = null; for (var i in line_path) { var current_path = line_path[i]; // Loop over vertex, exit when at last vertex for (var j = 0 ; j < Count(current_path) - 1 ; j++) { var from_coord = current_path[j]; var to_coord = current_path[j + 1]; var shortest = pDistance(point_coord[0], point_coord[1], from_coord[0], from_coord[1], to_coord[0],to_coord[1]); var distance = shortest[0]; var coordinates = shortest[1]; var isVertex = shortest[2]; if (distance <= min_distance) { // set the min distance of the current item min_distance = distance; var to_z = to_coord[2]; var from_z = from_coord[2]; // If the Z's are equal, no need to interpolate or check anything else if (to_z == from_z){ z_value = to_z; continue; } if (isVertex){ if (compare_coordinate(from_coord[0], from_coord[1],coordinates[0],coordinates[1])){ z_value = from_z; continue; } else if (compare_coordinate(to_coord[0], to_coord[1],coordinates[0],coordinates[1])){ z_value = to_z; continue; } } // Since the Zs are not equal and we are not at a vertex, we need to interpolate the z at the location var dist_to_point = Sqrt( (coordinates[0] - from_coord[0]) * Exp(2) + (coordinates[1] - from_coord[0])* Exp(2)) var dist_of_seg = Sqrt( (to_coord[0] - from_coord[0]) * Exp(2) + (to_coord[1] - from_coord[0])* Exp(2)) var percent_along = (dist_to_point/ dist_of_seg) var z_dif = Abs(to_z - from_z) z_value = z_dif * percent_along } } } return z_value } function compare_coordinate(x, y, x1, y1) { // TODO, probably move to Equals and compare the geometry if ((Round(x1, compare_coordinate_round_value) != Round(x, compare_coordinate_round_value)) || (Round(y1, compare_coordinate_round_value) != Round(y, compare_coordinate_round_value)) ){ return false; } return true; // TODO - Figure out Z if (Count(coordinate > 2) && IsEmpty(source_geo.Z) == false) { if (Round(coordinate[2], 2) != Round(source_geo.Z, 2)) { return false; } } return true; } function pDistance(x, y, x1, y1, x2, y2) { // adopted from https://stackoverflow.com/a/6853926 var A = x - x1; var B = y - y1; var C = x2 - x1; var D = y2 - y1; var dot = A * C + B * D; var len_sq = C * C + D * D; var param = -1; if (len_sq != 0) //in case of 0 length line param = dot / len_sq; var xx, yy; var is_vertex = false; if (compare_coordinate(x, y, x1, y1)) { is_vertex = true; } if (compare_coordinate(x, y, x2, y2)) { is_vertex = true; } if (param < 0) { // is_vertex = true; xx = x1; yy = y1; } else if (param > 1) { // is_vertex = true; xx = x2; yy = y2; } else { // is_vertex = false; xx = x1 + param * C; yy = y1 + param * D; } var dx = x - xx; var dy = y - yy; return [Sqrt(dx * dx + dy * dy), [xx, yy], is_vertex]; } // Used to check different empty null states, override of core IsEmpty function IsEmptyButBetter(data) { if (IsEmpty(data)) return true; for (var x in data) return false; return true; } var feat_geo = Geometry($feature); var lines = FeatureSetByName($map, "linefeature", ["globalId"], false) var intersected_line = First(Intersects(lines, $feature)); if (intersected_line == null ){ return Geometry($feature); } var new_z = get_z_at_location(Geometry(intersected_line),feat_geo) // NOTE: It would be much better to not assign this rule to the Geometry field and leave the field assignment null // then use the return edits dictionary to only update the geometry when the Z changes. This save the edit event in // an update event scenario. I just did nto have the time to look up the return edit syntax, exercise is left to the // reader var new_point = Point({ "x": feat_geo.x, "y":feat_geo.y, "z": new_z, "spatialReference": feat_geo.spatialReference }); return new_point

Re: [Arcade] Get z-Value from intersecting feature

StefanAngerer — Fri, 11 Nov 2022 11:57:00 GMT

Hmm, strange. Maybe I have the luck that the line features I am intersecting are all on the same hight? Because I actually managed to get my desired results with the simple code from above. Obiously this approach would fail if there where more vertices with different hight properties. Definitly something I have to consider.

Re: [Arcade] Get z-Value from intersecting feature

MikeMillerGIS — Fri, 11 Nov 2022 11:59:48 GMT

Correct, if the line has all the same Z's, easypeasy. But the reality is that a line may have different z's at every vertex.

Re: [Arcade] Get z-Value from intersecting feature

StefanAngerer — Fri, 11 Nov 2022 12:08:14 GMT

Alright. In this case I will have a look on that as well, for a more functional solution. Thanks for the help!

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Re: [Arcade] Get z-Value from intersecting feature