Firstly, I am new to using Mapwingis.ocx, so I apologise if I have overlooked something simple to resolve the problem outlined below. I have created a GIS application using Visual Basic (in Visual Studio 2010) – so far so good; all is functioning well. However, there is one problem I have not been able to resolve, so I am looking for some help to find a solution.
The problem relates to the distance values that are generated for polygons when interacting with the map. I am getting a disparity in distance values with latitude. For example, if I programmatically create a 1 hectare polygon (100m x 100m) at the equator, it is created fine; but if I create it at 51.7 degrees latitude (in the UK), the polygon created is 62m x 62m. A similar disparity in the distance occurs if I create a buffer around a shape (setting 100m buffer results in a 62m buffer on the map). Hence, I would like to know if there is something that I have overlooked that is causing this problem. I have tried changing the projection, geoprojection, mapunits, changing the tile provider (or having no tiles), and/or using the Utils ConvertDistance function, but none have worked; and I am struggling to find any further potential solutions online.
The settings I have in the application are:
- AxMap1.Projection = MapWinGIS.tkMapProjection.PROJECTION_GOOGLE_MERCATOR
- AxMap1.TileProvider = MapWinGIS.tkTileProvider.BingMaps
- AxMap1…MapUnits = tkUnitsOfMeasure.umMeters
Any help to point me in the right direction would be much appreciated. Happy to provide any further information to help resolve this.