Labels.DynamicVisibility makes labels disappear

MapWinGIS
1

Hello. I want the labels to be visible within a certain scale. When I zoom the map to a certain scale, the labels on the map are visible. When I zoom out the map to a certain scale, the labels on the map are not visible. I found two functions, Labels.MinVisibleScale and Labels.MaxVisibleScale. However, when I set DynamicVisibility to true, no matter how I modify the values of MaxVisibleScale and MinVisibleScale, these labels are not visible. The code is shown below. Where is the problem?

https://www.mapwindow.org/documentation/mapwingis4.9/group__labels__visibility.html#ga8046d21eefd1af4f7ca8382298e8916a

        Shapefile sf = new Shapefile();
        sf.CreateNew("", ShpfileType.SHP_POINT);
        Shape shp = new Shape();
        shp.Create(ShpfileType.SHP_POINT);

        MapWinGIS.Point pt = new MapWinGIS.Point();
        pt.x = 3;
        pt.y = 3;

        int index1 = shp.numPoints;
        shp.InsertPoint(pt, ref index1);

        int index2 = sf.NumShapes;
        sf.EditInsertShape(shp, ref index2);

        sf.Labels.AddLabel("label", 3, 3);
        sf.Labels.DynamicVisibility = true;
        sf.Labels.MaxVisibleScale = 10000000000000000;
        sf.Labels.MinVisibleScale = 0;

        axMap1.AddLayer(sf, true);
2

Can anyone help me? Thanks.
Or is it because I did n’t describe clearly?

3

Hello @Henry

I may have time to look at this later, but I believe it has to do with not having Projections or Tiles established, which establish map Scale and Zoom levels.

Jerry.

4

Ok, it looks like all you have to do is set a projection, something like

axMap1.Projection = tkMapProjection.PROJECTION_GOOGLE_MERCATOR;

I just doesn’t understand the concept of zoom levels or scale until a projection is set.

Regards,
Jerry.

5

Thanks a lot. It workes.

I use the MapWinGIS control as a CAD control. I mainly used to draw CAD graphics, so no projection was set. Now I set AxMap.Tiles.Provider property to ProviderNone, and change AxMap.Tiles.Visible property to false. In this way, I can continue to use it. Hope it will run well.

axMap1.TileProvider = tkTileProvider.ProviderNone;

Best wishes.
Henry