/// <summary>
/// Expand a geometry's extent - Help Map zoom to the geometry
/// </summary>
/// <param name="geometry">Geometry parameter: Point, Polyline, or Polygon</param>
/// <param name="percent">Percentage to expand the geometry's extent</param>
/// <returns>An expanded envelope</returns>
public static Envelope ExpandGeometryExtent(Geometry geometry, double percent)
{
if (geometry != null && Application.Current.RootVisual != null)
{
Envelope ext = geometry.Extent;
ScaleLine.ScaleLineUnit mapUnits = (Application.Current.RootVisual as MapPage).MapUnits;
double radiusX = MINIMUM_MAP_WIDTH / 2.0;
double radiusY = MINIMUM_MAP_WIDTH / 2.0;
double minimum = MINIMUM_MAP_WIDTH;
if (mapUnits == ScaleLine.ScaleLineUnit.DecimalDegrees)
{
double[] conversion = UnitsHelper.GetConversionToDegree((ext.YMin + ext.YMax) / 2.0, ScaleLine.ScaleLineUnit.Meters);
radiusX *= conversion[0];
radiusY *= conversion[1];
minimum *= conversion[0];
}
else
{
double conversion = UnitsHelper.GetConversionFromMeter(mapUnits);
radiusX *= conversion;
radiusY *= conversion;
minimum *= conversion;
}
double bufferX = (ext.Width < minimum) ? radiusX : (ext.Width * percent / 2.0);
double bufferY = (ext.Height < minimum) ? radiusY : (ext.Height * percent / 2.0);
ext.XMin = ext.XMin - bufferX;
ext.XMax = ext.XMax + bufferX;
ext.YMin = ext.YMin - bufferY;
ext.YMax = ext.YMax + bufferY;
return(ext);
}
else
{
return(null);
}
}
private Polygon CreateBufferCircle(MapPoint center, double radius, bool toMercator)
{
double pi36 = Math.PI / 180.0;
double rx = radius, ry = radius;
double dx = 1.0, dy = 1.0;
ScaleLine.ScaleLineUnit units = UnitsHelper.GetUnitsByWKID(center.SpatialReference.WKID);
if (units == ScaleLine.ScaleLineUnit.DecimalDegrees)
{
double[] conversion = UnitsHelper.GetConversionToDegree(center.Y, ScaleLine.ScaleLineUnit.Meters);
rx = radius * conversion[0];
ry = radius * conversion[1];
}
else
{
double conversion = UnitsHelper.GetConversionFromMeter(units);
rx = radius * conversion;
ry = radius * conversion;
}
PointCollection pointSet = new PointCollection();
for (int i = 0; i <= 36; i++)
{
dx = center.X + rx * Math.Cos(i * 10 * pi36);
dy = center.Y + ry * Math.Sin(i * 10 * pi36);
MapPoint p = new MapPoint(dx, dy, new SpatialReference(center.SpatialReference.WKID));
pointSet.Add((center.SpatialReference.WKID == 4326 && toMercator) ? p.GeographicToWebMercator() : p);
}
Polygon circle = new Polygon();
circle.Rings.Add(pointSet);
circle.SpatialReference = new SpatialReference((center.SpatialReference.WKID == 4326 && toMercator) ? 102113 : center.SpatialReference.WKID);
return(circle);
}
