/// <summary>
/// Add a point to the polygon or polyline.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="lat">The latitude of the point (degrees).</param>
/// <param name="lon">The longitude of the point (degrees).</param>
/// <remarks>
/// g and p must have been initialized with calls to geod_init() and
/// geod_polygon_init(), respectively. The same g must be used for all the
/// points and edges in a polygon. lat should be in the range
/// [-90deg, 90deg] and lon should be in the range [-540deg, 540deg).
/// </remarks>
public void geod_polygon_addpoint(geod_geodesic g, double lat, double lon)
{
lon = AngNormalize(lon);
if (num == 0)
{
lat0 = this.lat = lat;
lon0 = this.lon = lon;
}
else
{
double s12, S12 = 0, dummy;
if (polyline)
{
g.geod_geninverse(this.lat, this.lon, lat, lon, GEOD.DISTANCE, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
}
else
{
g.geod_geninverse(this.lat, this.lon, lat, lon, GEOD.DISTANCE | GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
}
accadd(P, s12);
if (!polyline)
{
accadd(A, S12);
crossings += transit(this.lon, lon);
}
this.lat = lat; this.lon = lon;
}
++num;
}
/// <summary>
/// A simple interface for computing the area of a geodesic polygon.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="lats">An array of latitudes of the polygon vertices (degrees).</param>
/// <param name="lons">An array of longitudes of the polygon vertices (degrees).</param>
/// <param name="n">The number of vertices.</param>
/// <param name="pA">The area of the polygon (square meters).</param>
/// <param name="pP">The perimeter of the polygon (meters).</param>
/// <remarks>
/// lats should be in the range [-90deg, 90deg]; lons should be in the range [-540deg, 540deg).
///
/// Only simple polygons (which are not self-intersecting) are allowed.
/// There's no need to "close" the polygon by repeating the first vertex. The
/// area returned is signed with counter-clockwise traversal being treated as
/// positive.
/// </remarks>
public static void geod_polygonarea(geod_geodesic g, double[] lats, double[] lons, int n, out double pA, out double pP)
{
geod_polygon p = new geod_polygon(false);
for (int i = 0; i < n; ++i)
{
p.geod_polygon_addpoint(g, lats[i], lons[i]);
}
p.geod_polygon_compute(g, false, true, out pA, out pP);
}
/// <summary>
/// Add an edge to the polygon or polyline.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="azi">The azimuth at current point (degrees).</param>
/// <param name="s">The distance from current point to next point (meters).</param>
/// <remarks>
/// g and p must have been initialized with calls to geod_init() and
/// geod_polygon_init(), respectively. The same g must be used for all the
/// points and edges in a polygon. azi should be in the range
/// [-540deg, 540deg). This does nothing if no points have been
/// added yet. The lat and lon fields of p give the location of
/// the new vertex.
/// </remarks>
public void geod_polygon_addedge(geod_geodesic g, double azi, double s)
{
if (num != 0)
{ // Do nothing is num is zero
double lat, lon, S12 = 0, dummy;
if (polyline)
{
g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE | GEOD.LONGITUDE, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
}
else
{
g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE | GEOD.LONGITUDE | GEOD.AREA, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
}
accadd(P, s);
if (!polyline)
{
accadd(A, S12);
crossings += transitdirect(this.lon, lon);
}
this.lat = lat; this.lon = lon;
++num;
}
}
/// <summary>
/// Return the results assuming a tentative final test point is added via an
/// azimuth and distance; however, the data for the test point is not saved.
/// This lets you report a running result for the perimeter and area as the
/// user moves the mouse cursor. Ordinary floating point arithmetic is used
/// to accumulate the data for the test point; thus the area and perimeter
/// returned are less accurate than if geod_polygon_addedge() and
/// geod_polygon_compute() are used.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="azi">The azimuth at current point (degrees).</param>
/// <param name="s">The distance from current point to final test point (meters).</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// azi should be in the range [-540deg, 540deg).
/// </remarks>
public int geod_polygon_testedge(geod_geodesic g, double azi, double s, bool reverse, bool sign, out double pA, out double pP)
{
pP = pA = NaN;
int num = this.num + 1;
if (num == 1)
{
return(0); // we don't have a starting point!
}
double perimeter = P[0] + s;
if (polyline)
{
pP = perimeter;
return(num);
}
double tempsum = A[0];
int crossings = this.crossings;
{
double lat, lon, s12, S12, dummy;
g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE | GEOD.LONGITUDE | GEOD.AREA, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
tempsum += S12;
crossings += transitdirect(this.lon, lon);
g.geod_geninverse(lat, lon, lat0, lon0, GEOD.DISTANCE | GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
perimeter += s12;
tempsum += S12;
crossings += transit(lon, lon0);
}
double area0 = 4 * pi * g.c2;
if ((crossings & 1) != 0)
{
tempsum += (tempsum < 0?1:-1) * area0 / 2;
}
// area is with the clockwise sense. If !reverse convert to counter-clockwise convention.
if (!reverse)
{
tempsum *= -1;
}
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if (sign)
{
if (tempsum > area0 / 2)
{
tempsum -= area0;
}
else if (tempsum <= -area0 / 2)
{
tempsum += area0;
}
}
else
{
if (tempsum >= area0)
{
tempsum -= area0;
}
else if (tempsum < 0)
{
tempsum += area0;
}
}
pP = perimeter;
pA = 0 + tempsum;
return(num);
}
/// <summary>
/// Return the results assuming a tentative final test point is added;
/// however, the data for the test point is not saved. This lets you report a
/// running result for the perimeter and area as the user moves the mouse
/// cursor. Ordinary floating point arithmetic is used to accumulate the data
/// for the test point; thus the area and perimeter returned are less accurate
/// than if geod_polygon_addpoint() and geod_polygon_compute() are used.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="lat">The latitude of the test point (degrees).</param>
/// <param name="lon">The longitude of the test point (degrees).</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// lat should be in the range [-90deg, 90deg] and lon should be in the range [-540deg, 540deg).
/// </remarks>
public int geod_polygon_testpoint(geod_geodesic g, double lat, double lon, bool reverse, bool sign, out double pA, out double pP)
{
pP = pA = 0;
int num = this.num + 1;
if (num == 1)
{
return(num);
}
double perimeter = P[0];
double tempsum = polyline?0:A[0];
int crossings = this.crossings;
for (int i = 0; i < (polyline?1:2); ++i)
{
double s12, dummy;
if (!polyline)
{
double S12;
g.geod_geninverse(i == 0?this.lat:lat, i == 0?this.lon:lon, i != 0?lat0:lat, i != 0?lon0:lon, GEOD.DISTANCE | GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
tempsum += S12;
crossings += transit(i == 0?this.lon:lon, i != 0?this.lon0:lon);
}
else
{
g.geod_geninverse(i == 0?this.lat:lat, i == 0?this.lon:lon, i != 0?lat0:lat, i != 0?lon0:lon, GEOD.DISTANCE, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
}
perimeter += s12;
}
pP = perimeter;
if (polyline)
{
return(num);
}
double area0 = 4 * pi * g.c2;
if ((crossings & 1) != 0)
{
tempsum += (tempsum < 0?1:-1) * area0 / 2;
}
// area is with the clockwise sense. If !reverse convert to counter-clockwise convention.
if (!reverse)
{
tempsum *= -1;
}
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if (sign)
{
if (tempsum > area0 / 2)
{
tempsum -= area0;
}
else if (tempsum <= -area0 / 2)
{
tempsum += area0;
}
}
else
{
if (tempsum >= area0)
{
tempsum -= area0;
}
else if (tempsum < 0)
{
tempsum += area0;
}
}
pA = 0 + tempsum;
return(num);
}
/// <summary>
/// Return the results for a polygon.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// The area and perimeter are accumulated at two times the standard floating
/// point precision to guard against the loss of accuracy with many-sided
/// polygons. Only simple polygons (which are not self-intersecting) are
/// allowed. There's no need to "close" the polygon by repeating the first vertex.
/// </remarks>
public int geod_polygon_compute(geod_geodesic g, bool reverse, bool sign, out double pA, out double pP)
{
pP = pA = 0;
if (num < 2)
{
return(num);
}
if (polyline)
{
pP = P[0];
return(num);
}
double s12, S12, dummy;
g.geod_geninverse(lat, lon, lat0, lon0, GEOD.DISTANCE | GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
pP = accsum(P, s12);
double[] t = new double[2];
acccopy(A, t);
accadd(t, S12);
int crossings = this.crossings + transit(lon, lon0);
double area0 = 4 * pi * g.c2;
if ((crossings & 1) != 0)
{
accadd(t, (t[0] < 0?1:-1) * area0 / 2);
}
// area is with the clockwise sense. If !reverse convert to
// counter-clockwise convention.
if (!reverse)
{
accneg(t);
}
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if (sign)
{
if (t[0] > area0 / 2)
{
accadd(t, -area0);
}
else if (t[0] <= -area0 / 2)
{
accadd(t, +area0);
}
}
else
{
if (t[0] >= area0)
{
accadd(t, -area0);
}
else if (t[0] < 0)
{
accadd(t, +area0);
}
}
pA = 0 + t[0];
return(num);
}
public override PJ Init()
{
g = new geod_geodesic(a, es / (1 + Math.Sqrt(one_es)));
phi0 = Proj.pj_param_r(ctx, parameters, "lat_0");
if (Math.Abs(Math.Abs(phi0) - Proj.HALFPI) < EPS10)
{
mode = phi0 < 0.0?aeqd_mode.S_POLE:aeqd_mode.N_POLE;
sinph0 = phi0 < 0.0?-1.0:1.0;
cosph0 = 0.0;
}
else if (Math.Abs(phi0) < EPS10)
{
mode = aeqd_mode.EQUIT;
sinph0 = 0.0;
cosph0 = 1.0;
}
else
{
mode = aeqd_mode.OBLIQ;
sinph0 = Math.Sin(phi0);
cosph0 = Math.Cos(phi0);
}
if (es == 0)
{
inv = s_inverse;
fwd = s_forward;
}
else
{
en = Proj.pj_enfn(es);
if (en == null)
{
return(null);
}
if (Proj.pj_param_b(ctx, parameters, "guam"))
{
M1 = Proj.pj_mlfn(phi0, sinph0, cosph0, en);
inv = e_guam_inv;
fwd = e_guam_fwd;
}
else
{
switch (mode)
{
case aeqd_mode.N_POLE:
Mp = Proj.pj_mlfn(Proj.HALFPI, 1.0, 0.0, en);
break;
case aeqd_mode.S_POLE:
Mp = Proj.pj_mlfn(-Proj.HALFPI, -1.0, 0.0, en);
break;
case aeqd_mode.EQUIT:
case aeqd_mode.OBLIQ:
inv = e_inverse;
fwd = e_forward;
N1 = 1.0 / Math.Sqrt(1.0 - es * sinph0 * sinph0);
He = e / Math.Sqrt(one_es);
G = sinph0 * He;
He *= cosph0;
break;
}
inv = e_inverse;
fwd = e_forward;
}
}
return(this);
}
public void Ini()
{
GlobalGeodesic = new geod_geodesic(geod_a, geod_f);
}
/// <summary>
/// Return the results assuming a tentative final test point is added;
/// however, the data for the test point is not saved. This lets you report a
/// running result for the perimeter and area as the user moves the mouse
/// cursor. Ordinary floating point arithmetic is used to accumulate the data
/// for the test point; thus the area and perimeter returned are less accurate
/// than if geod_polygon_addpoint() and geod_polygon_compute() are used.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="lat">The latitude of the test point (degrees).</param>
/// <param name="lon">The longitude of the test point (degrees).</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// lat should be in the range [-90deg, 90deg] and lon should be in the range [-540deg, 540deg).
/// </remarks>
public int geod_polygon_testpoint(geod_geodesic g, double lat, double lon, bool reverse, bool sign, out double pA, out double pP)
{
pP=pA=0;
int num=this.num+1;
if(num==1) return num;
double perimeter=P[0];
double tempsum=polyline?0:A[0];
int crossings=this.crossings;
for(int i=0; i<(polyline?1:2); ++i)
{
double s12, dummy;
if(!polyline)
{
double S12;
g.geod_geninverse(i==0?this.lat:lat, i==0?this.lon:lon, i!=0?lat0:lat, i!=0?lon0:lon, GEOD.DISTANCE|GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
tempsum+=S12;
crossings+=transit(i==0?this.lon:lon, i!=0?this.lon0:lon);
}
else g.geod_geninverse(i==0?this.lat:lat, i==0?this.lon:lon, i!=0?lat0:lat, i!=0?lon0:lon, GEOD.DISTANCE, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
perimeter+=s12;
}
pP=perimeter;
if(polyline) return num;
double area0=4*pi*g.c2;
if((crossings&1)!=0) tempsum+=(tempsum<0?1:-1)*area0/2;
// area is with the clockwise sense. If !reverse convert to counter-clockwise convention.
if(!reverse) tempsum*=-1;
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if(sign)
{
if(tempsum>area0/2) tempsum-=area0;
else if(tempsum<=-area0/2) tempsum+=area0;
}
else
{
if(tempsum>=area0) tempsum-=area0;
else if(tempsum<0) tempsum+=area0;
}
pA=0+tempsum;
return num;
}
/// <summary>
/// A simple interface for computing the area of a geodesic polygon.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="lats">An array of latitudes of the polygon vertices (degrees).</param>
/// <param name="lons">An array of longitudes of the polygon vertices (degrees).</param>
/// <param name="n">The number of vertices.</param>
/// <param name="pA">The area of the polygon (square meters).</param>
/// <param name="pP">The perimeter of the polygon (meters).</param>
/// <remarks>
/// lats should be in the range [-90deg, 90deg]; lons should be in the range [-540deg, 540deg).
///
/// Only simple polygons (which are not self-intersecting) are allowed.
/// There's no need to "close" the polygon by repeating the first vertex. The
/// area returned is signed with counter-clockwise traversal being treated as
/// positive.
/// </remarks>
public static void geod_polygonarea(geod_geodesic g, double[] lats, double[] lons, int n, out double pA, out double pP)
{
geod_polygon p=new geod_polygon(false);
for(int i=0; i<n; ++i) p.geod_polygon_addpoint(g, lats[i], lons[i]);
p.geod_polygon_compute(g, false, true, out pA, out pP);
}
/// <summary>
/// Return the results assuming a tentative final test point is added via an
/// azimuth and distance; however, the data for the test point is not saved.
/// This lets you report a running result for the perimeter and area as the
/// user moves the mouse cursor. Ordinary floating point arithmetic is used
/// to accumulate the data for the test point; thus the area and perimeter
/// returned are less accurate than if geod_polygon_addedge() and
/// geod_polygon_compute() are used.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="azi">The azimuth at current point (degrees).</param>
/// <param name="s">The distance from current point to final test point (meters).</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// azi should be in the range [-540deg, 540deg).
/// </remarks>
public int geod_polygon_testedge(geod_geodesic g, double azi, double s, bool reverse, bool sign, out double pA, out double pP)
{
pP=pA=NaN;
int num=this.num+1;
if(num==1) return 0; // we don't have a starting point!
double perimeter=P[0]+s;
if(polyline)
{
pP=perimeter;
return num;
}
double tempsum=A[0];
int crossings=this.crossings;
{
double lat, lon, s12, S12, dummy;
g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE|GEOD.LONGITUDE|GEOD.AREA, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
tempsum+=S12;
crossings+=transitdirect(this.lon, lon);
g.geod_geninverse(lat, lon, lat0, lon0, GEOD.DISTANCE|GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
perimeter+=s12;
tempsum+=S12;
crossings+=transit(lon, lon0);
}
double area0=4*pi*g.c2;
if((crossings&1)!=0) tempsum+=(tempsum<0?1:-1)*area0/2;
// area is with the clockwise sense. If !reverse convert to counter-clockwise convention.
if(!reverse) tempsum*=-1;
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if(sign)
{
if(tempsum>area0/2) tempsum-=area0;
else if(tempsum<=-area0/2) tempsum+=area0;
}
else
{
if(tempsum>=area0) tempsum-=area0;
else if(tempsum<0) tempsum+=area0;
}
pP=perimeter;
pA=0+tempsum;
return num;
}
/// <summary>
/// Return the results for a polygon.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="reverse">If set <b>true</b> then clockwise (instead of counter-clockwise)
/// traversal counts as a positive area.</param>
/// <param name="sign">If set <b>true</b> then return a signed result for the area if the
/// polygon is traversed in the "wrong" direction instead of returning the area for the
/// rest of the earth.</param>
/// <param name="pA">The area of the polygon (square meters); only set if polyline is set <b>true</b>
/// in the call to geod_polygon_init().</param>
/// <param name="pP">The perimeter of the polygon or length of the polyline (meters).</param>
/// <returns>The number of points.</returns>
/// <remarks>
/// The area and perimeter are accumulated at two times the standard floating
/// point precision to guard against the loss of accuracy with many-sided
/// polygons. Only simple polygons (which are not self-intersecting) are
/// allowed. There's no need to "close" the polygon by repeating the first vertex.
/// </remarks>
public int geod_polygon_compute(geod_geodesic g, bool reverse, bool sign, out double pA, out double pP)
{
pP=pA=0;
if(num<2) return num;
if(polyline)
{
pP=P[0];
return num;
}
double s12, S12, dummy;
g.geod_geninverse(lat, lon, lat0, lon0, GEOD.DISTANCE|GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
pP=accsum(P, s12);
double[] t=new double[2];
acccopy(A, t);
accadd(t, S12);
int crossings=this.crossings+transit(lon, lon0);
double area0=4*pi*g.c2;
if((crossings&1)!=0) accadd(t, (t[0]<0?1:-1)*area0/2);
// area is with the clockwise sense. If !reverse convert to
// counter-clockwise convention.
if(!reverse) accneg(t);
// If sign put area in (-area0/2, area0/2], else put area in [0, area0)
if(sign)
{
if(t[0]>area0/2) accadd(t, -area0);
else if(t[0]<=-area0/2) accadd(t, +area0);
}
else
{
if(t[0]>=area0) accadd(t, -area0);
else if(t[0]<0) accadd(t, +area0);
}
pA=0+t[0];
return num;
}
/// <summary>
/// Add a point to the polygon or polyline.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="lat">The latitude of the point (degrees).</param>
/// <param name="lon">The longitude of the point (degrees).</param>
/// <remarks>
/// g and p must have been initialized with calls to geod_init() and
/// geod_polygon_init(), respectively. The same g must be used for all the
/// points and edges in a polygon. lat should be in the range
/// [-90deg, 90deg] and lon should be in the range [-540deg, 540deg).
/// </remarks>
public void geod_polygon_addpoint(geod_geodesic g, double lat, double lon)
{
lon=AngNormalize(lon);
if(num==0)
{
lat0=this.lat=lat;
lon0=this.lon=lon;
}
else
{
double s12, S12=0, dummy;
if(polyline) g.geod_geninverse(this.lat, this.lon, lat, lon, GEOD.DISTANCE, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
else g.geod_geninverse(this.lat, this.lon, lat, lon, GEOD.DISTANCE|GEOD.AREA, out s12, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
accadd(P, s12);
if(!polyline)
{
accadd(A, S12);
crossings+=transit(this.lon, lon);
}
this.lat=lat; this.lon=lon;
}
++num;
}
/// <summary>
/// Add an edge to the polygon or polyline.
/// </summary>
/// <param name="g">The geod_geodesic object specifying the ellipsoid.</param>
/// <param name="p">The geod_polygon object specifying the polygon.</param>
/// <param name="azi">The azimuth at current point (degrees).</param>
/// <param name="s">The distance from current point to next point (meters).</param>
/// <remarks>
/// g and p must have been initialized with calls to geod_init() and
/// geod_polygon_init(), respectively. The same g must be used for all the
/// points and edges in a polygon. azi should be in the range
/// [-540deg, 540deg). This does nothing if no points have been
/// added yet. The lat and lon fields of p give the location of
/// the new vertex.
/// </remarks>
public void geod_polygon_addedge(geod_geodesic g, double azi, double s)
{
if(num!=0)
{ // Do nothing is num is zero
double lat, lon, S12=0, dummy;
if(polyline) g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE|GEOD.LONGITUDE, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out dummy);
else g.geod_gendirect(this.lat, this.lon, azi, GEOD.LONG_UNROLL, s, GEOD.LATITUDE|GEOD.LONGITUDE|GEOD.AREA, out lat, out lon, out dummy, out dummy, out dummy, out dummy, out dummy, out S12);
accadd(P, s);
if(!polyline)
{
accadd(A, S12);
crossings+=transitdirect(this.lon, lon);
}
this.lat=lat; this.lon=lon;
++num;
}
}
/// <summary>
/// Initialize a geod_geodesicline object.
/// </summary>
/// <param name="g">The <see cref="geod_geodesic"/> object specifying the ellipsoid.</param>
/// <param name="lat1">Latitude of point 1 (degrees).</param>
/// <param name="lon1">Longitude of point 1 (degrees).</param>
/// <param name="azi1">Azimuth at point 1 (degrees).</param>
/// <param name="caps">Bitor'ed combination of <see cref="geod_mask"/> values. See remarks for more informations.</param>
/// <remarks>
/// <paramref name="caps"/> bitor'ed combination of geod_mask() values specifying
/// the capabilities the geod_geodesicline object should possess, i.e., which
/// quantities can be returned in calls to geod_position() and
/// geod_genposition().
///
/// <paramref name="lat1"/> should be in the range [-90deg, 90deg].
/// <paramref name="lon1"/> and <paramref name="azi1"/> should be in the range [-540deg, 540deg).
///
/// The geod_mask values are:
/// - caps|=GEOD_LATITUDE for the latitude lat2; this is added automatically,
/// - caps|=GEOD_LONGITUDE for the latitude lon2,
/// - caps|=GEOD_AZIMUTH for the latitude azi2; this is added automatically,
/// - caps|=GEOD_DISTANCE for the distance s12,
/// - caps|=GEOD_REDUCEDLENGTH for the reduced length m12,
/// - caps|=GEOD_GEODESICSCALE for the geodesic scales M12 and M21,
/// - caps|=GEOD_AREA for the area S12,
/// - caps|=GEOD_DISTANCE_IN permits the length of the
/// geodesic to be given in terms of s12; without this capability the
/// length can only be specified in terms of arc length.
///
/// A value of caps=0 is treated as GEOD.LATITUDE|GEOD.LONGITUDE|GEOD.AZIMUTH|GEOD.DISTANCE_IN
/// (to support the solution of the "standard" direct problem).
/// </remarks>
public geod_geodesicline(geod_geodesic g, double lat1, double lon1, double azi1, GEOD caps)
{
a = g.a;
f = g.f;
b = g.b;
c2 = g.c2;
f1 = g.f1;
// If caps is 0 assume the standard direct calculation
this.caps = (caps != 0?caps:GEOD.DISTANCE_IN | GEOD.LONGITUDE) |
GEOD.LATITUDE | GEOD.AZIMUTH | GEOD.LONG_UNROLL; // always allow latitude and azimuth and unrolling of longitude
this.lat1 = lat1;
this.lon1 = lon1;
// Guard against underflow in salp0
this.azi1 = AngRound(AngNormalize(azi1));
// alp1 is in [0, pi]
double alp1 = this.azi1 * degree;
// Enforce sin(pi)==0 and cos(pi/2)==0. Better to face the ensuing
// problems directly than to skirt them.
salp1 = this.azi1 == -180?0:Math.Sin(alp1);
calp1 = Math.Abs(this.azi1) == 90?0:Math.Cos(alp1);
double phi = lat1 * degree;
// Ensure cbet1=+epsilon at poles
double sbet1 = f1 * Math.Sin(phi);
double cbet1 = Math.Abs(lat1) == 90?tiny:Math.Cos(phi);
norm2(ref sbet1, ref cbet1);
dn1 = Math.Sqrt(1 + g.ep2 * sq(sbet1));
// Evaluate alp0 from sin(alp1)*cos(bet1)=sin(alp0),
salp0 = salp1 * cbet1; // alp0 in [0, pi/2-|bet1|]
// Alt: calp0=hypot(sbet1, calp1*cbet1). The following
// is slightly better (consider the case salp1=0).
calp0 = hypotx(calp1, salp1 * sbet1);
// Evaluate sig with tan(bet1)=tan(sig1)*cos(alp1).
// sig = 0 is nearest northward crossing of equator.
// With bet1=0, alp1=pi/2, we have sig1=0 (equatorial line).
// With bet1=pi/2, alp1=-pi, sig1=pi/2
// With bet1=-pi/2, alp1=0, sig1=-pi/2
// Evaluate omg1 with tan(omg1)=sin(alp0)*tan(sig1).
// With alp0 in (0, pi/2], quadrants for sig and omg coincide.
// No atan2(0, 0) ambiguity at poles since cbet1=+epsilon.
// With alp0=0, omg1=0 for alp1=0, omg1=pi for alp1=pi.
ssig1 = sbet1; somg1 = salp0 * sbet1;
csig1 = comg1 = sbet1 != 0 || calp1 != 0?cbet1 * calp1:1;
norm2(ref ssig1, ref csig1); // sig1 in (-pi, pi]
// norm2(ref somg1, ref comg1); -- don't need to normalize!
k2 = sq(calp0) * g.ep2;
double eps = k2 / (2 * (1 + Math.Sqrt(1 + k2)) + k2);
if ((this.caps & GEOD.CAP_C1) != 0)
{
double s, c;
A1m1 = geod_geodesic.A1m1f(eps);
geod_geodesic.C1f(eps, C1a);
B11 = SinCosSeries(true, ssig1, csig1, C1a, nC1);
s = Math.Sin(B11); c = Math.Cos(B11);
// tau1=sig1+B11
stau1 = ssig1 * c + csig1 * s;
ctau1 = csig1 * c - ssig1 * s;
// Not necessary because C1pa reverts C1a
// B11=-SinCosSeries(TRUE, stau1, ctau1, C1pa, nC1p);
}
if ((this.caps & GEOD.CAP_C1p) != 0)
{
geod_geodesic.C1pf(eps, C1pa);
}
if ((this.caps & GEOD.CAP_C2) != 0)
{
A2m1 = geod_geodesic.A2m1f(eps);
geod_geodesic.C2f(eps, C2a);
B21 = SinCosSeries(true, ssig1, csig1, C2a, nC2);
}
if ((this.caps & GEOD.CAP_C3) != 0)
{
g.C3f(eps, C3a);
A3c = -f *salp0 *g.A3f(eps);
B31 = SinCosSeries(true, ssig1, csig1, C3a, nC3 - 1);
}
if ((this.caps & GEOD.CAP_C4) != 0)
{
g.C4f(eps, C4a);
// Multiplier=a^2*e^2*cos(alpha0)*sin(alpha0)
A4 = sq(a) * calp0 * salp0 * g.e2;
B41 = SinCosSeries(false, ssig1, csig1, C4a, nC4);
}
}
