/// <summary>
/// Calculates the scale at the center of a polygon, at a given pixel size
/// </summary>
/// <remarks>
/// A pixel is a device independent logical pixel - ie 1/96 inches.
/// </remarks>
/// <param name="visibleArea">The area which center the scale will be calculated for.</param>
/// <param name="unitsPerPixel">The size of a device indepedent pixel in the units of the spatial reference</param>
/// <returns>The MapScale for the center of the view</returns>
public static double CalculateScale(Esri.ArcGISRuntime.Geometry.Polygon visibleArea, double unitsPerPixel)
{
if (visibleArea == null)
{
return(double.NaN);
}
if (visibleArea.SpatialReference == null)
{
return(double.NaN);
}
if (double.IsNaN(unitsPerPixel) || unitsPerPixel <= 0)
{
return(double.NaN);
}
var center = visibleArea.Extent.GetCenter();
var centerOnePixelOver = new Geometry.MapPoint(center.X + unitsPerPixel, center.Y, center.SpatialReference);
// Calculate the geodedetic distance between two points one 'pixel' apart
var result = Geometry.GeometryEngine.DistanceGeodetic(center, centerOnePixelOver, Geometry.LinearUnits.Inches, Geometry.AngularUnits.Degrees, Geometry.GeodeticCurveType.Geodesic);
double distanceInInches = result.Distance;
return(distanceInInches * 96);
}
/// <summary>
/// Calculates the scale at the center of a polygon, at a given pixel size.
/// </summary>
/// <remarks>
/// A pixel is a device independent logical pixel - ie 1/96 inches.
/// </remarks>
/// <param name="visibleArea">The area which center the scale will be calculated for.</param>
/// <param name="unitsPerPixel">The size of a device indepedent pixel in the units of the spatial reference.</param>
/// <returns>The MapScale for the center of the view.</returns>
public static double CalculateScale(Esri.ArcGISRuntime.Geometry.Polygon?visibleArea, double unitsPerPixel)
{
if (visibleArea == null)
{
return(double.NaN);
}
if (visibleArea.SpatialReference == null)
{
return(double.NaN);
}
if (double.IsNaN(unitsPerPixel) || unitsPerPixel <= 0)
{
return(double.NaN);
}
#if __ANDROID__
// Need to convert the value to DIPs
unitsPerPixel /= Android.Util.TypedValue.ApplyDimension(Android.Util.ComplexUnitType.Dip, 1, Internal.ViewExtensions.GetDisplayMetrics());
#endif
var center = visibleArea.Extent.GetCenter();
var centerOnePixelOver = new Geometry.MapPoint(center.X + unitsPerPixel, center.Y, center.SpatialReference);
// Calculate the geodedetic distance between two points one 'pixel' apart
var result = Geometry.GeometryEngine.DistanceGeodetic(center, centerOnePixelOver, Geometry.LinearUnits.Inches, Geometry.AngularUnits.Degrees, Geometry.GeodeticCurveType.Geodesic);
double distanceInInches = result !.Distance;
return(distanceInInches * 96);
}
