idea Arcade: Snap point to polyline (mid-segment) in ArcGIS Pro Ideas

Arcade: Snap point to polyline (mid-segment)

Bud — Mon, 21 Mar 2022 10:44:13 GMT

Could an Arcade function be added to do the following:

Snap a point to a polyline — but snap it mid-segment, not just to the closest vertex.

The function would return the snapped point — as well as return the ID of the polyline the point was snapped to.

Thanks.

Re: Arcade: Snap point to polyline (mid-segment)

JohannesLindner — Mon, 21 Mar 2022 06:46:32 GMT

Yes, a snap function would be great.

In the meantime, you can do it yourself (this is in multiple of my Calculation Attribute Rules):

function closest_feature(test_feature, compare_feature_set) { // returns the feature of compare_feature_set that is closest to test_feature var min_distance = 9999999 var closest_feature = null for(var f in compare_feature_set) { var d = Distance(test_feature, f) if(d < min_distance) { min_distance = d closest_feature = f } } return closest_feature } function project_orthogonally(point_geometry, line_geometry) { // returns a projection of the point_geometry onto the line_geometry // only start and end point of the line_geometry are considered! // https://de.wikipedia.org/wiki/Orthogonalprojektion // https://en.wikibooks.org/wiki/Linear_Algebra/Orthogonal_Projection_Onto_a_Line var p = point_geometry var r0 = line_geometry.paths[0][0] var r1 = line_geometry.paths[0][-1] var ux = r1.x - r0.x var uy = r1.y - r0.y var lambda = ((p.x-r0.x)*ux + (p.y-r0.y)*uy) / (ux*ux + uy*uy) var new_p = Point({"x": r0.x + lambda * ux, "y": r0.y + lambda * uy, "spatialReference": p.spatialReference}) // if new_p is on the line defined by r0 and r1 but not on the actual line_geometry, snap it to the closest end point if(Disjoint(new_p, line_geometry)) { new_p = IIF(Distance(r0, p) < Distance(r1, p), r0, r1) } return new_p } function snap_point_to_polyline(point_geometry, polyline_geometry) { // returns a point that is snapped to the polyline_geometry // create feature set of the polyline's segments var sr = point_geometry.spatialReference var vertices = polyline_geometry.paths[0] var fs_segments = {"fields": [], "spatialReference": sr, "geometryType": "esriGeometryPolyline", "features": []} for(var s=0; s<Count(vertices)-1; s++) { var p0 = vertices[s] var p1 = vertices[s+1] Push(fs_segments.features, {"geometry": {"paths": [[ [p0.x, p0.y], [p1.x, p1.y] ]], "spatialReference": sr}}) } fs_segments = FeatureSet(Text(fs_segments)) // project point_geometry onto the closest segment var closest_segment_geo = Geometry(closest_feature(point_geometry, fs_segments)) return project_orthogonally(point_geometry, closest_segment_geo ) } var fs_lines = FeatureSetByName($datastore, "Lines") // optionally, buffer fs_lines = Intersects(fs_lines, Buffer($feature, 100)) var closest_line_geometry = Geometry(closest_feature($feature, fs_lines)) return snap_point_to_polyline(Geometry($feature), closest_line_geometry)

Re: Arcade: Snap point to polyline (mid-segment)

Bud — Wed, 30 Mar 2022 16:54:25 GMT

Attribute Rules Blog: Auto Snapping with Attribute rules during Editing

Re: Arcade: Snap point to polyline (mid-segment)

Bud — Mon, 10 Jul 2023 17:32:32 GMT

New Arcade functions in Arcade v1.23:

Although, I don't think those functions help with "snapping mid-segment".

Re: Arcade: Snap point to polyline (mid-segment)

JohannesLindner — Tue, 11 Jul 2023 17:52:26 GMT

Ooh, I missed that update, thanks for the link!

It actually does solve your problem.

function closest_feature(test_feature, compare_feature_set) { // ... } function project_orthogonally(point_geometry, line_geometry) { // ... } function snap_point_to_polyline(point_geometry, polyline_geometry) { // ... } var line = Polyline({ paths: [[ [0, 0], [1, 1], [1, 5], ]], spatialReference: {wkid: 3857} }) var p = Point({x: 2, y: 2, spatialReference: {wkid: 3857}}) var sp1 = snap_point_to_polyline(p, line) var sp2 = NearestCoordinate(line, p).coordinate Console("With 3 custom functions: " + sp1) Console("With NearestCoordinate: " + sp2)

With 3 custom functions: {"spatialReference":{"wkid":3857},"x":1,"y":2}
With NearestCoordinate: {"spatialReference":{"wkid":3857},"x":1,"y":2}