/// <summary>
/// Retruns the equivalent distance on the mapping plane.
/// </summary>
/// <param name="from">The position the distance is measured from.</param>
/// <param name="to">The approximate end position.</param>
/// <param name="sys">The mapping system</param>
/// <returns>The distance on the mapping plane.</returns>
internal double GetPlanarMetric(IPosition from, IPosition to, ISpatialSystem sys)
{
if (!this.IsDefined)
{
return(0.0);
}
double sfac = sys.GetLineScaleFactor(from, to);
return(m_ObservedMetric * sfac);
}
/// <summary>
/// Returns the equivalent distance on the mapping plane.
/// </summary>
/// <param name="from">The position the distance is measured from.</param>
/// <param name="bearing">The bearing for the distance, in radians.</param>
/// <param name="sys">The mapping system</param>
/// <returns>The distance on the mapping plane.</returns>
internal double GetPlanarMetric(IPosition from, double bearing, ISpatialSystem sys)
{
// Return zero if this distance is undefined.
if (!this.IsDefined)
{
return(0.0);
}
// Calculate approximation for the terminal position (treating
// this distance as a planar distance).
IPosition to = Geom.Polar(from, bearing, m_ObservedMetric);
// Use the approximate location to determine line scale factor
double sfac = sys.GetLineScaleFactor(from, to);
return(m_ObservedMetric * sfac);
}
/// <summary>
/// Returns a formatted distance string.
/// </summary>
/// <param name="metric">The distance on the mapping plane (in meters).</param>
/// <param name="from">The start position.</param>
/// <param name="to">The end position.</param>
/// <returns>The formatted distance</returns>
protected string Format(double metric, IPosition from, IPosition to)
{
if (m_Unit == null)
{
m_Distance = String.Empty;
}
else
{
// Get the fixed number of significant digits to show.
int prec = -1;
if (m_Unit.UnitType == DistanceUnitType.Meters)
{
prec = 3;
}
else if (m_Unit.UnitType == DistanceUnitType.Feet)
{
prec = 2;
}
else if (m_Unit.UnitType == DistanceUnitType.Chains)
{
prec = 4;
}
// Get string for the planar distance.
string pstring = m_Unit.Format(metric, true, prec);
// Get string for the ground distance (don't bother with
// units abbreviation).
ISpatialSystem sys = CadastralMapModel.Current.SpatialSystem;
double sfac = sys.GetLineScaleFactor(from, to);
double gmetric = metric / sfac;
string gstring = m_Unit.Format(gmetric, false, prec);
// Format the complete string.
m_Distance = String.Format("{0} ({1} on ground)", pstring, gstring);
}
return(m_Distance);
}
/// <summary>
/// Calculates the position of the sideshot point.
/// </summary>
/// <param name="dir">The direction observation (if any).</param>
/// <param name="len">The length observation (if any). Could be a <c>Distance</c> or an
/// <c>OffsetPoint</c>.</param>
/// <returns>The position of the sideshot point (null if there is insufficient data
/// to calculate a position)</returns>
internal static IPosition Calculate(Direction dir, Observation len)
{
// Return if there is insufficient data.
if (dir == null || len == null)
{
return(null);
}
// Get the position of the point the sideshot should radiate from.
PointFeature from = dir.From;
// Get the position of the start of the direction line (which may be offset).
IPosition start = dir.StartPosition;
// Get the bearing of the direction.
double bearing = dir.Bearing.Radians;
// Get the length of the sideshot arm.
double length = len.GetDistance(from).Meters;
// Calculate the resultant position. Note that the length is the length along the
// bearing -- if an offset was specified, the actual length of the line from-to =
// sqrt(offset*offset + length*length)
IPosition to = Geom.Polar(start, bearing, length);
// Return if the length is an offset point. In that case, the length we have obtained
// is already a length on the mapping plane, so no further reduction should be done
// (although it's debateable).
if (len is OffsetPoint)
{
return(to);
}
// Using the position we've just got, reduce the length we used to a length on the
// mapping plane (it's actually a length on the ground).
ISpatialSystem sys = CadastralMapModel.Current.SpatialSystem;
double sfac = sys.GetLineScaleFactor(start, to);
return(Geom.Polar(start, bearing, length * sfac));
}
/// <summary>
/// Calculates intersection points.
/// </summary>
/// <param name="dist1">1st distance observation.</param>
/// <param name="from1">The point the 1st distance was observed from.</param>
/// <param name="dist2">2nd distance observation.</param>
/// <param name="from2">The point the 2nd distance was observed from.</param>
/// <param name="usedefault">True if the default intersection is required (the one that has the
/// lowest bearing with respect to the 2 from points). False for the other one (if any).</param>
/// <param name="xsect">The position of the intersection (if any).</param>
/// <param name="xsect1">The 1st choice intersection (if any).</param>
/// <param name="xsect2">The 2nd choice intersection (if any).</param>
/// <returns>True if intersections were calculated. False if the distance circles
/// don't intersect.</returns>
internal static bool Calculate(Observation dist1, PointFeature from1, Observation dist2, PointFeature from2, bool usedefault,
out IPosition xsect, out IPosition xsect1, out IPosition xsect2)
{
// Initialize intersection positions.
xsect = xsect1 = xsect2 = null;
// Get the 2 distances.
double d1 = dist1.GetDistance(from1).Meters;
double d2 = dist2.GetDistance(from2).Meters;
if (d1 < Constants.TINY || d2 < Constants.TINY)
{
return(false);
}
// Form circles with radii that match the observed distances.
ICircleGeometry circle1 = new CircleGeometry(from1, d1);
ICircleGeometry circle2 = new CircleGeometry(from2, d2);
// See if there is actually an intersection between the two circles.
IPosition x1, x2;
uint nx = IntersectionHelper.Intersect(circle1, circle2, out x1, out x2);
if (nx == 0)
{
return(false);
}
// If we have 2 intersections, and we need the non-default one, pick up the 2nd
// intersection. If only 1 intersection, use that, regardless of the setting for
// the "use default" flag.
if (nx == 2 && !usedefault)
{
xsect = x2;
}
else
{
xsect = x1;
}
// Return if both distances are offset points.
OffsetPoint offset1 = (dist1 as OffsetPoint);
OffsetPoint offset2 = (dist2 as OffsetPoint);
if (offset1 != null && offset2 != null)
{
xsect1 = x1;
xsect2 = x2;
return(true);
}
// Reduce observed distances to the mapping plane.
ISpatialSystem sys = CadastralMapModel.Current.SpatialSystem;
if (offset1 == null)
{
d1 = d1 * sys.GetLineScaleFactor(from1, xsect);
}
if (offset2 == null)
{
d2 = d2 * sys.GetLineScaleFactor(from2, xsect);
}
// And calculate the exact intersection (like above)...
// Form circles with radii that match the observed distances.
ICircleGeometry circle1p = new CircleGeometry(from1, d1);
ICircleGeometry circle2p = new CircleGeometry(from2, d2);
// See if there is still an intersection between the two circles.
nx = IntersectionHelper.Intersect(circle1p, circle2p, out x1, out x2);
if (nx == 0)
{
return(false);
}
// If we have 2 intersections, and we need the non-default one, pick up the 2nd
// intersection. If only 1 intersection, use that, regardless of the setting for
// the "use default" flag.
if (nx == 2 && !usedefault)
{
xsect = x2;
}
else
{
xsect = x1;
}
xsect1 = x1;
xsect2 = x2;
return(true);
}
/// <summary>
/// Calculates the intersection point.
/// </summary>
/// <param name="dir">Direction observation.</param>
/// <param name="distance">Distance observation.</param>
/// <param name="from">The point the distance was observed from.</param>
/// <param name="usedefault">True if the default intersection is required (the one
/// closer to the origin of the direction line). False for the other one (if any).</param>
/// <param name="xsect">The position of the intersection (if any).</param>
/// <param name="xsect1">The 1st choice intersection (if any).</param>
/// <param name="xsect2">The 2nd choice intersection (if any).</param>
/// <returns>True if intersections were calculated. False if the distance circles
/// don't intersect.</returns>
internal static bool Calculate(Direction dir, Observation distance, PointFeature from, bool usedefault,
out IPosition xsect, out IPosition xsect1, out IPosition xsect2)
{
// Initialize intersection positions.
xsect = xsect1 = xsect2 = null;
// Get the distance.
double dist = distance.GetDistance(from).Meters;
if (dist < Constants.TINY)
{
return(false);
}
// Form circle with a radius that matches the observed distance.
ICircleGeometry circle = new CircleGeometry(from, dist);
// See if there is actually an intersection between the direction & the circle.
IPosition x1, x2;
uint nx = dir.Intersect(circle, out x1, out x2);
if (nx == 0)
{
return(false);
}
// If we have 2 intersections, and we need the non-default one, pick up the 2nd
// intersection. If only 1 intersection, use that, regardless of the setting for
// the "use default" flag.
if (nx == 2 && !usedefault)
{
xsect = x2;
}
else
{
xsect = x1;
}
// Return if the distance is an offset point.
OffsetPoint offset = (distance as OffsetPoint);
if (offset != null)
{
xsect1 = x1;
xsect2 = x2;
return(true);
}
// Reduce observed distance to the mapping plane.
ISpatialSystem sys = CadastralMapModel.Current.SpatialSystem;
dist = dist * sys.GetLineScaleFactor(from, xsect);
// And calculate the exact intersection (like above)...
// Form circle with a radius that matches the reduced distance.
ICircleGeometry circlep = new CircleGeometry(from, dist);
// See if there is actually an intersection between the direction & the circle.
nx = dir.Intersect(circlep, out x1, out x2);
if (nx == 0)
{
return(false);
}
// If we have 2 intersections, and we need the non-default one, pick up the 2nd
// intersection. If only 1 intersection, use that, regardless of the setting for
// the "use default" flag.
if (nx == 2 && !usedefault)
{
xsect = x2;
}
else
{
xsect = x1;
}
xsect1 = x1;
xsect2 = x2;
return(true);
}
