Snapping to a polyline feature

KevinCheriyan — Fri, 02 Jul 2021 20:04:52 GMT

I have an app in AppStudio that contains a map with several feature layers. The user for the application will be interacting with the layers and submitting data from app to elsewhere. I want the user to be able to click on the map (it will never be exact, therefore reasonably close) near a line feature and retrieve the coordinates for the nearest point on the line.

For example, user clicks on or near the polyline feature. This creates a Graphic that is snapped to the nearest point on the polyline feature. This allows the app to retrieve coordinates where the user tapped on the feature.

This is the workflow I would like to implement:

1) User clicks on or near polyline feature

2) Get the coordinates for the point that user tapped on and calculate distance x to polyline feature (using Geometry Engine's distance method).

3) Plot point on line that is x distance away from tapped point to line feature.

4) Place a Graphic on this final point on the line feature to indicate that the snapping has completed.

How can I achieve step 3? I have a distance that I can calculate successfully. Is the best way to do this by calculating a buffer with x radius and then finding points of intersection with the line feature? Or is there a better way? All I want to do is just snap this point that is not on the line to the line.

Thanks for the help!

Re: Snapping to a polyline feature

JamesBallard1 — Fri, 02 Jul 2021 21:24:21 GMT

Hi @KevinCheriyan,

We have a sample that has nearly the exact workflow you're looking for. It shows how to get the distance and "snap" a mouse click to a polyline (in the case of the sample, it's the edge of a polygon).

https://github.com/Esri/arcgis-runtime-samples-qt/tree/main/ArcGISRuntimeSDKQt_QMLSamples/Geometry/NearestVertex

Let us know if this help.

Re: Snapping to a polyline feature

KevinCheriyan — Tue, 06 Jul 2021 19:51:37 GMT

Thanks, @JamesBallard1 ! This worked perfectly. I swear I must've looked over the methods in GeometryEngine a few times, but still missed these!

topic Snapping to a polyline feature in Qt Maps SDK Questions

Snapping to a polyline feature

Re: Snapping to a polyline feature

Re: Snapping to a polyline feature