topic Labels not showing on polygon in .NET Maps SDK Questions

Labels not showing on polygon

Moer — Thu, 30 Dec 2021 13:57:59 GMT

(UWP, 100.12 & 100.13)

Some polygons don't display the label that is specified on the overlay.

I have extracted some code to a demo project that shows the problem. I have added three polygons to an overlay and added a symbol renderer and a label definition. The large polygon doesn't show the label.

Code extract (see full demo in attached zip):

testLayer = new GraphicsOverlay { Id = "TEST_LAYER", RenderingMode = GraphicsRenderingMode.Static, LabelsEnabled = true, }; //Symbol renderer testLayer.Renderer = new SimpleRenderer(new SimpleLineSymbol { Color = Color.Yellow, Style = SimpleLineSymbolStyle.Solid, Width = 2 }); //Label def var label = new LabelDefinition(new SimpleLabelExpression($"\"Test\""), new TextSymbol { BackgroundColor = Color.Aqua, Color = Color.Black, Size = 14 });

Re: Labels not showing on polygon

JohannesLindner — Mon, 03 Jan 2022 08:40:37 GMT

Have you checked that your geometries are OK? An invalid geometry will display on the map but won't show a label. If this is what's wrong, running the RepairGeometries tool should solve it.

https://desktop.arcgis.com/en/arcmap/10.3/tools/data-management-toolbox/check-geometry.htm

https://desktop.arcgis.com/en/arcmap/10.3/tools/data-management-toolbox/repair-geometry.htm

Re: Labels not showing on polygon

TonyWakim — Tue, 04 Jan 2022 19:19:20 GMT

Calling "poly = GeometryEngine.Simplify(poly);" on your polygon before adding it to the GraphicsOverlay should resolve the issue.

private void addPolygon(string polygonJson) { var poly = Geometry.FromJson(polygonJson); poly = GeometryEngine.Simplify(poly); var graphic = new Graphic { Geometry = GeometryEngine.Project((Polygon)poly, new SpatialReference(3006)) }; testLayer.Graphics.Add(graphic); }

Re: Labels not showing on polygon

ofirrosner — Thu, 26 Sep 2024 06:36:52 GMT

I know its an old question, but WHY does it work?