114 lines
4 KiB
C++
114 lines
4 KiB
C++
// ATCProjection.cxx - A convienience projection class for the ATC/AI system.
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//
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// Written by David Luff, started 2002.
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//
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// Copyright (C) 2002 David C Luff - david.luff@nottingham.ac.uk
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of the
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// License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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#include "ATCProjection.hxx"
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#include <math.h>
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#include <simgear/constants.h>
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FGATCProjection::FGATCProjection() {
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_origin.setlat(0.0);
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_origin.setlon(0.0);
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_origin.setelev(0.0);
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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FGATCProjection::FGATCProjection(const Point3D& centre) {
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_origin = centre;
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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FGATCProjection::~FGATCProjection() {
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}
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void FGATCProjection::Init(const Point3D& centre) {
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_origin = centre;
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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Point3D FGATCProjection::ConvertToLocal(const Point3D& pt) {
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double delta_lat = pt.lat() - _origin.lat();
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double delta_lon = pt.lon() - _origin.lon();
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double y = sin(delta_lat * SG_DEGREES_TO_RADIANS) * SG_EQUATORIAL_RADIUS_M;
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double x = sin(delta_lon * SG_DEGREES_TO_RADIANS) * SG_EQUATORIAL_RADIUS_M * _correction_factor;
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return(Point3D(x,y,0.0));
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}
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Point3D FGATCProjection::ConvertFromLocal(const Point3D& pt) {
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double delta_lat = asin(pt.y() / SG_EQUATORIAL_RADIUS_M) * SG_RADIANS_TO_DEGREES;
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double delta_lon = (asin(pt.x() / SG_EQUATORIAL_RADIUS_M) * SG_RADIANS_TO_DEGREES) / _correction_factor;
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return(Point3D(_origin.lon()+delta_lon, _origin.lat()+delta_lat, 0.0));
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}
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/**********************************************************************************/
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FGATCAlignedProjection::FGATCAlignedProjection() {
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_origin.setlat(0.0);
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_origin.setlon(0.0);
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_origin.setelev(0.0);
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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FGATCAlignedProjection::FGATCAlignedProjection(const Point3D& centre, double heading) {
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_origin = centre;
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_theta = heading * SG_DEGREES_TO_RADIANS;
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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FGATCAlignedProjection::~FGATCAlignedProjection() {
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}
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void FGATCAlignedProjection::Init(const Point3D& centre, double heading) {
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_origin = centre;
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_theta = heading * SG_DEGREES_TO_RADIANS;
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_correction_factor = cos(_origin.lat() * SG_DEGREES_TO_RADIANS);
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}
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Point3D FGATCAlignedProjection::ConvertToLocal(const Point3D& pt) {
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// convert from lat/lon to orthogonal
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double delta_lat = pt.lat() - _origin.lat();
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double delta_lon = pt.lon() - _origin.lon();
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double y = sin(delta_lat * SG_DEGREES_TO_RADIANS) * SG_EQUATORIAL_RADIUS_M;
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double x = sin(delta_lon * SG_DEGREES_TO_RADIANS) * SG_EQUATORIAL_RADIUS_M * _correction_factor;
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// Align
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if(_theta != 0.0) {
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double xbar = x;
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x = x*cos(_theta) - y*sin(_theta);
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y = (xbar*sin(_theta)) + (y*cos(_theta));
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}
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return(Point3D(x,y,pt.elev()));
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}
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Point3D FGATCAlignedProjection::ConvertFromLocal(const Point3D& pt) {
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// de-align
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double thi = _theta * -1.0;
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double x = pt.x()*cos(thi) - pt.y()*sin(thi);
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double y = (pt.x()*sin(thi)) + (pt.y()*cos(thi));
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// convert from orthogonal to lat/lon
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double delta_lat = asin(y / SG_EQUATORIAL_RADIUS_M) * SG_RADIANS_TO_DEGREES;
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double delta_lon = (asin(x / SG_EQUATORIAL_RADIUS_M) * SG_RADIANS_TO_DEGREES) / _correction_factor;
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return(Point3D(_origin.lon()+delta_lon, _origin.lat()+delta_lat, pt.elev()));
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}
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