// Calculates the linear distance between two user-defined geometries
private async void DistanceButton_Click(object sender, RoutedEventArgs e)
{
try
{
txtResults.Visibility = Visibility.Collapsed;
_graphicsOverlay.Graphics.Clear();
// wait for user to draw a polyline
var line = await MyMapView.Editor.RequestShapeAsync(DrawShape.Polyline, _lineSymbol);
_graphicsOverlay.Graphics.Add(new Graphic(line, _lineSymbol));
// wait for user to draw a point
var point = await MyMapView.Editor.RequestPointAsync();
_graphicsOverlay.Graphics.Add(new Graphic(point, _pointSymbol));
// Calculate distance between line and point
double distance = GeometryEngine.Distance(line, point) * METERS_TO_MILES;
txtResults.Text = string.Format("Distance between geometries: {0:0.000} miles", distance);
txtResults.Visibility = Visibility.Visible;
}
catch (Exception ex)
{
var _x = new MessageDialog("Distance Calculation Error: " + ex.Message, "Sample Error").ShowAsync();
txtResults.Visibility = Visibility.Collapsed;
_graphicsOverlay.Graphics.Clear();
}
}
// calculates how far down a line a certain point on the line is located as a value from 0..1
private double GetFractionAlongLine(Polyline segment, ProximityResult proximity, MapPoint location)
{
double distance1 = 0;
double distance2 = 0;
int pointIndex = proximity.PointIndex;
int vertexCount = segment.Parts.GetPartsAsPoints().First().Count();
var vertexPoint = segment.Parts.GetPartsAsPoints().ElementAt(proximity.PartIndex).ElementAt(pointIndex);
MapPoint previousPoint;
int onSegmentIndex = 0;
//Detect which line segment we currently are on
if (pointIndex == 0) //Snapped to first vertex
{
onSegmentIndex = 0;
}
else if (pointIndex == vertexCount - 1) //Snapped to last vertex
{
onSegmentIndex = segment.Parts.GetPartsAsPoints().First().Count() - 2;
}
else
{
MapPoint nextPoint = segment.Parts.GetPartsAsPoints().First().ElementAt(pointIndex + 1);
var d1 = GeometryEngine.Distance(vertexPoint, nextPoint);
var d2 = GeometryEngine.Distance(location, nextPoint);
if (d1 < d2)
{
onSegmentIndex = pointIndex - 1;
}
else
{
onSegmentIndex = pointIndex;
}
}
previousPoint = segment.Parts.GetPartsAsPoints().First().First();
for (int j = 1; j < onSegmentIndex + 1; j++)
{
MapPoint point = segment.Parts.GetPartsAsPoints().First().ElementAt(j);
distance1 += GeometryEngine.Distance(previousPoint, point);
previousPoint = point;
}
distance1 += GeometryEngine.Distance(previousPoint, location);
previousPoint = segment.Parts.GetPartsAsPoints().First().ElementAt(onSegmentIndex + 1);
distance2 = GeometryEngine.Distance(location, previousPoint);
previousPoint = vertexPoint;
for (int j = onSegmentIndex + 2; j < segment.Parts[0].Count; j++)
{
MapPoint point = segment.Parts.GetPartsAsPoints().First().ElementAt(j);
distance2 += GeometryEngine.Distance(previousPoint, point);
previousPoint = point;
}
//var previousPoint = proximity.PointIndex ? segment.GetPoint(proximity.PartIndex + 1, 0) : segment.GetPoint(proximity.PartIndex, proximity.PointIndex + 1);
if (distance1 + distance2 == 0)
{
return(1);
}
return(distance1 / (distance1 + distance2));
}
public void UpdateMapPointToScale()
{
Point secondP = new Point(0, 1);
_mapPointToScale = _MyMapView.ScreenToLocation(secondP);
Scale = GeometryEngine.Distance(_BBox_Left_Top, _mapPointToScale) / 1.735;
//return a;
}
/// <summary>
/// Create a circular polygon around a mappoint for with a radius in pixels.
/// </summary>
/// <param name="mapPoint">Center of the circle as a mappoint.</param>
/// <param name="pixels">Circle radius in screen pixels.</param>
/// <returns>A polygon geometry.</returns>
private Polygon CreateSearchPolygon(MapPoint mapPoint, int pixels)
{
//get search radius
var screenPoint = MapView.Active.MapToScreen(mapPoint);
var radiusScreenPoint = new System.Windows.Point((screenPoint.X + pixels), screenPoint.Y);
var radiusMapPoint = MapView.Active.ScreenToMap(radiusScreenPoint);
var searchRadius = GeometryEngine.Distance(mapPoint, radiusMapPoint);
//build a search circle geometry
var cent = new Coordinate2D(mapPoint);
var searchGeom = EllipticArcBuilder.CreateEllipticArcSegment(cent, searchRadius, esriArcOrientation.esriArcClockwise, MapView.Active.Map.SpatialReference);
var searchPB = new PolygonBuilder(new[] { searchGeom });
return(searchPB.ToGeometry());
}
private async void QueryFeatures(Geometry buffer, MapPoint location)
{
//create query
var query = new QueryParameters();
query.Geometry = buffer;
query.MaxAllowableOffset = 0;
System.Diagnostics.Debug.WriteLine(buffer.ToJson());
var layer = MyMapView.Map.OperationalLayers[0] as FeatureLayer;
var table = layer.FeatureTable;
var results = await table.QueryFeaturesAsync(query);
layer.ClearSelection();
/* // ===================================================================
* // Single Closest Bar
* // -------------------------------------------------------------------
*
* double shortDist = -1;
* Feature feature = null;
*
* //check for closest bars within buffer
* foreach (var item in results)
* {
* var calcDistance = GeometryEngine.Distance(location, item.Geometry);
*
* if (shortDist == -1)
* {
* shortDist = calcDistance;
* feature = item;
* continue;
* }
*
* if (calcDistance < shortDist)
* {
* shortDist = calcDistance;
* feature = item;
* }
* }
*
* //exit if no closest bar
* if (feature == null)
* return;
*
* if (!(GeometryEngine.Intersects(buffer, feature.Geometry)))
* return;
*
* //highlight closest bar
* layer.SelectFeature(feature);
* layer.SelectionColor = Colors.DarkRed;
*
* //draw line to closest bar
* var linePoints = new PolylineBuilder(SpatialReferences.WebMercator);
* linePoints.AddPoint(location);
* linePoints.AddPoint(feature.Geometry as MapPoint);
* var line = linePoints.ToGeometry();
*
* var lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.DashDotDot, Colors.Maroon, 2);
* var lineGraphic = new Graphic(line, lineSymbol);
* MyOverlay.Graphics.Add(lineGraphic);
*
*
* //create text symbol for distance at midpoint of line
* var x = (line.Extent.XMin + line.Extent.XMax) / 2;
* var y = (line.Extent.YMin + line.Extent.YMax) / 2;
* var textPoint = new MapPoint(x, y);
* var text = String.Format("{0:0.00}", shortDist / 1609.34) + " miles";
* var textSymbol = new TextSymbol(text, Colors.Black, 15, Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Center, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Baseline);
* textSymbol.FontWeight = Esri.ArcGISRuntime.Symbology.FontWeight.Bold;
* //textSymbol.BackgroundColor = Colors.Maroon;
* //textSymbol.Angle = Math.Atan2(line.Extent.YMax - line.Extent.YMin, line.Extent.XMax - line.Extent.XMin) * 180.0 / Math.PI;
* var textGraphic = new Graphic(textPoint, textSymbol);
* MyOverlay.Graphics.Add(textGraphic);
*
* //===================================================================*/
//==================================================================
// Two Closest Bars
//------------------------------------------------------------------
double[] shortDist = { -1, -1 };
Feature[] feature = new Feature[2];
System.Diagnostics.Debug.WriteLine("#1: shortdist is at: " + shortDist[0].ToString() + " " + shortDist[1].ToString());
//check for closest bars within buffer
foreach (var item in results)
{
var calcDistance = GeometryEngine.Distance(location, item.Geometry);
System.Diagnostics.Debug.WriteLine("feature distance: " + (calcDistance / 1609.34).ToString() + " meters; shordist = " + shortDist[0].ToString() + " " + shortDist[1].ToString());
if (shortDist[0] == -1)
{
shortDist[0] = calcDistance;
System.Diagnostics.Debug.WriteLine("setting first");
feature[0] = item;
continue;
}
if (shortDist[1] == -1)
{
System.Diagnostics.Debug.WriteLine("setting second");
shortDist[1] = calcDistance;
feature[1] = item;
continue;
}
if (calcDistance < shortDist[0])
{
System.Diagnostics.Debug.WriteLine("less than first");
shortDist[1] = shortDist[0];
feature[1] = feature[0];
shortDist[0] = calcDistance;
feature[0] = item;
}
else if (calcDistance < shortDist[1])
{
System.Diagnostics.Debug.WriteLine("less than second");
shortDist[1] = calcDistance;
feature[1] = item;
}
}
//exit if no closest bar
if (feature[0] == null || feature[1] == null)
{
return;
}
if (!(GeometryEngine.Intersects(buffer, feature[0].Geometry)))
{
return;
}
//highlight closest bar
for (int i = 0; i < 2; i++)
{
layer.SelectFeature(feature[i]);
layer.SelectionColor = Colors.DarkRed;
//draw line to closest bar
var linePoints = new PolylineBuilder(SpatialReferences.WebMercator);
linePoints.AddPoint(location);
linePoints.AddPoint(feature[i].Geometry as MapPoint);
var line = linePoints.ToGeometry();
var lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.DashDotDot, Colors.Maroon, 2);
var lineGraphic = new Graphic(line, lineSymbol);
MyOverlay.Graphics.Add(lineGraphic);
//create text symbol for distance at midpoint of line
var x = (line.Extent.XMin + line.Extent.XMax) / 2;
var y = (line.Extent.YMin + line.Extent.YMax) / 2;
var textPoint = new MapPoint(x, y);
var text = String.Format("{0:0.00}", shortDist[i] / 1609.34) + " miles";
var textSymbol = new TextSymbol(text, Colors.Black, 15, Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Center, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Baseline);
textSymbol.FontWeight = Esri.ArcGISRuntime.Symbology.FontWeight.Bold;
//textSymbol.BackgroundColor = Colors.Maroon;
//textSymbol.Angle = Math.Atan2(line.Extent.YMax - line.Extent.YMin, line.Extent.XMax - line.Extent.XMin) * 180.0 / Math.PI;
var textGraphic = new Graphic(textPoint, textSymbol);
MyOverlay.Graphics.Add(textGraphic);
}
}