/// <summary>
/// Try to initialize the map units
/// </summary>
private void InitializeMapUnit()
{
if (Map == null || Map.SpatialReference == null)
{
return;
}
// First test the well know spatial references
if (Map.SpatialReference.WKID == 4326)
{
MapUnit = ScaleLineUnit.DecimalDegrees;
}
else if (_webMercSref.Equals(Map.SpatialReference))
{
MapUnit = ScaleLineUnit.Meters;
}
else
{
Layer layer = Map.Layers == null ? null :
Map.Layers.FirstOrDefault(l => l.SpatialReference != null && l.SpatialReference.Equals(Map.SpatialReference));
string layerUnits;
if (layer is ArcGISDynamicMapServiceLayer)
{
layerUnits = ((ArcGISDynamicMapServiceLayer)layer).Units;
}
else if (layer is ArcGISTiledMapServiceLayer)
{
layerUnits = ((ArcGISTiledMapServiceLayer)layer).Units;
}
else
{
layerUnits = null;
}
if (!string.IsNullOrEmpty(layerUnits))
{
// Remove leading 'esri' to layerUnits
if (layerUnits.StartsWith("esri"))
{
layerUnits = layerUnits.Substring(4);
}
try
{
ScaleLineUnit unit = (ScaleLineUnit)Enum.Parse(typeof(ScaleLineUnit), layerUnits, true);
MapUnit = unit;
}
catch (ArgumentException) // layersUnits is not one of the named constants defined for the enumeration
{
}
}
}
}
private double GetBestEstimateOfValue(double resolution, ScaleLineUnit displayUnit, out ScaleLineUnit unit, out double outResolution)
{
unit = displayUnit;
double rounded = 0;
double originalRes = resolution;
while (rounded < 0.5)
{
resolution = originalRes;
if (MapUnit == ScaleLineUnit.DecimalDegrees)
{
resolution = GetResolutionForGeographic(Map.Extent.GetCenter(), resolution);
resolution = resolution * (int)ScaleLineUnit.Meters / (int)unit;
}
else if (_webMercSref.Equals(Map.SpatialReference))
{
//WebMercator
double mercatorStretch = 1 / Math.Cosh(Map.Extent.GetCenter().Y / earthRadius); // = Cos(lat)
resolution = mercatorStretch * originalRes * (int)ScaleLineUnit.Meters / (int)unit;
}
else if (MapUnit != ScaleLineUnit.Undefined)
{
resolution = resolution * (int)MapUnit / (int)unit;
}
double val = TargetWidth * resolution;
val = RoundToSignificant(val, resolution);
double noFrac = Math.Round(val); // to get rid of the fraction
if (val < 0.5)
{
ScaleLineUnit newUnit = ScaleLineUnit.Undefined;
// Automatically switch unit to a lower one
if (unit == ScaleLineUnit.Kilometers)
{
newUnit = ScaleLineUnit.Meters;
}
else if (unit == ScaleLineUnit.Miles)
{
newUnit = ScaleLineUnit.Feet;
}
if (newUnit == ScaleLineUnit.Undefined)
{
break;
} //no lower unit
unit = newUnit;
}
else if (noFrac > 1)
{
rounded = noFrac;
var len = noFrac.ToString("F0").Length; // Format F0 prevents from using exponential notation for big numbers
if (len <= 2)
{
// single/double digits ... make it a multiple of 5 ..or 1,2,3,4
if (noFrac > 5)
{
rounded -= noFrac % 5;
}
while (rounded > 1 && (rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. decrement by 1 or by 5
double decr = noFrac > 5 ? 5 : 1;
rounded = rounded - decr;
}
}
else if (len > 2)
{
rounded = Math.Round(noFrac / Math.Pow(10, len - 1)) * Math.Pow(10, len - 1);
if ((rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. use the lower bound instead
rounded = Math.Floor(noFrac / Math.Pow(10, len - 1)) * Math.Pow(10, len - 1);
}
}
}
else
{ // anything between 0.5 and 1
rounded = Math.Floor(val);
if (rounded == 0)
{
//val >= 0.5 but < 1 so round up
rounded = (val == 0.5) ? 0.5 : 1;
if ((rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. re-try by switching to lower unit
rounded = 0;
ScaleLineUnit newUnit = ScaleLineUnit.Undefined;
// Automatically switch unit to a lower one
if (unit == ScaleLineUnit.Kilometers)
{
newUnit = ScaleLineUnit.Meters;
}
else if (unit == ScaleLineUnit.Miles)
{
newUnit = ScaleLineUnit.Feet;
}
if (newUnit == ScaleLineUnit.Undefined)
{
break;
} //no lower unit
unit = newUnit;
}
}
}
}
outResolution = resolution;
return(rounded);
}
private double GetBestEstimateOfValue(double resolution, ScaleLineUnit displayUnit, out ScaleLineUnit unit, out double outResolution)
{
unit = displayUnit;
double rounded = 0;
double originalRes = resolution;
while (rounded < 0.5)
{
resolution = originalRes;
if (MapUnit == ScaleLineUnit.DecimalDegrees)
{
resolution = GetResolutionForGeographic(Map.Extent.GetCenter(), resolution);
resolution = resolution * (int)ScaleLineUnit.Meters / (int)unit;
}
else if (_webMercSref.Equals(Map.SpatialReference))
{
//WebMercator
double mercatorStretch = 1 / Math.Cosh(Map.Extent.GetCenter().Y / earthRadius); // = Cos(lat)
resolution = mercatorStretch * originalRes * (int)ScaleLineUnit.Meters / (int)unit;
}
else if (MapUnit != ScaleLineUnit.Undefined)
{
resolution = resolution * (int)MapUnit / (int)unit;
}
double val = TargetWidth * resolution;
val = RoundToSignificant(val, resolution);
double noFrac = Math.Round(val); // to get rid of the fraction
if (val < 0.5)
{
ScaleLineUnit newUnit = ScaleLineUnit.Undefined;
// Automatically switch unit to a lower one
if (unit == ScaleLineUnit.Kilometers)
newUnit = ScaleLineUnit.Meters;
else if (unit == ScaleLineUnit.Miles)
newUnit = ScaleLineUnit.Feet;
if (newUnit == ScaleLineUnit.Undefined) { break; } //no lower unit
unit = newUnit;
}
else if (noFrac > 1)
{
rounded = noFrac;
var len = noFrac.ToString().Length;
if (len <= 2)
{
// single/double digits ... make it a multiple of 5 ..or 1,2,3,4
if (noFrac > 5)
{
rounded -= noFrac % 5;
}
while (rounded > 1 && (rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. decrement by 1 or by 5
double decr = noFrac > 5 ? 5 : 1;
rounded = rounded - decr;
}
}
else if (len > 2)
{
rounded = Math.Round(noFrac / Math.Pow(10, len - 1)) * Math.Pow(10, len - 1);
if ((rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. use the lower bound instead
rounded = Math.Floor(noFrac / Math.Pow(10, len - 1)) * Math.Pow(10, len - 1);
}
}
}
else
{ // anything between 0.5 and 1
rounded = Math.Floor(val);
if (rounded == 0)
{
//val >= 0.5 but < 1 so round up
rounded = (val == 0.5) ? 0.5 : 1;
if ((rounded / resolution) > TargetWidth)
{
// exceeded maxWidth .. re-try by switching to lower unit
rounded = 0;
ScaleLineUnit newUnit = ScaleLineUnit.Undefined;
// Automatically switch unit to a lower one
if (unit == ScaleLineUnit.Kilometers)
newUnit = ScaleLineUnit.Meters;
else if (unit == ScaleLineUnit.Miles)
newUnit = ScaleLineUnit.Feet;
if (newUnit == ScaleLineUnit.Undefined) { break; } //no lower unit
unit = newUnit;
}
}
}
}
outResolution = resolution;
return rounded;
}
