Change projection

[Ioan]

I made a custom map provider for Yandex maps, but it seems Yandex is using projection.wgs84Mercator.
Pins on Bing and OpenStreet maps are positioned correctly but those on yandex are offseted.
Does RadMap support Yandex's projection?

[Ioan]

It seems RadMap doesn't support yandex projection projection.wgs84Mercator (EPSG:4326 ellipsoid). Can you please provide a starting point for creating my own projection?

[Petar Mladenov]

Hello Loan,

You can create custom map provider and override its SpatialRefence property which returns the projection.

public class MyMapProvider : TiledProvider
{
       /// <summary>
       /// Initializes a new instance of the MyMapProvider class.
       /// </summary>
       public MyMapProvider()
             : base()
       {
             MyMapSource source = new MyMapSource();
             this.MapSources.Add(source.UniqueId, source);
       }
       /// <summary>
       /// Returns the SpatialReference for the map provider.
       /// </summary>
       public override ISpatialReference SpatialReference
       {
             get
             {
                    return new MercatorProjection();
             }

We hope you can also find useful the following threads:

Custom Map Projection
Offline map Servier ( Andrey's post from 26. October 2011 )
 
Regards,
Petar Mladenov
Telerik

 

 

[Massimo]

Hi loan, have you succeeded?

Can telerik provide a little help to implement GeographicToLogical and LogicalToGeographic functions please?

[Petar Mladenov]

Hi Massimo,

Have you tried implementing custom projection by inheriting from our SpatialReference class. Basically it implements the mentioned GographicToLocigal and LogicalToGeographic functions:

/// <summary>
    /// The OGC Spatial Reference requirements.
    /// </summary>
    public class SpatialReference : ISpatialReference
....

 /// <summary>
        /// Converts a geographical coordinate (Longitude, Latitude) to a logical Point (0->1).
        /// </summary>
        /// <param name="geographicPoint">The geographical coordinate (Longitude, Latitude).</param>
        /// <returns>The logical Point.</returns>
        public virtual Point GeographicToLogical(Location geographicPoint)
        {
            double d = Math.Sin(geographicPoint.Latitude * this.AngularUnitOfMeasurement);

            Point point = new Point((geographicPoint.Longitude * this.AngularUnitOfMeasurement * this.ScaleX) + this.OffsetX,
                (0.5 * Math.Log((1.0 + d) / (1.0 - d)) * this.ScaleY) + this.OffsetY);

            if (point.Y > 1)
            {
                point.Y = 1;
            }

            return point;
        }

        /// <summary>
        /// Converts a logical Point (0->1) to a geographical coordinate (Longitude, Latitude).
        /// </summary>
        /// <param name="logicalPoint">The logical Point.</param>
        /// <returns>The geographical coordinate (Longitude, Latitude).</returns>
        public virtual Location LogicalToGeographic(Point logicalPoint)
        {
            return new Location(
                Math.Atan(Math.Sinh((logicalPoint.Y - this.OffsetY) / this.ScaleY)) * RadiansToDegrees,
                (logicalPoint.X - this.OffsetX) * RadiansToDegrees / this.ScaleX);
        }

Regards,
Petar Mladenov
Telerik by Progress