From 29efa84075311a079eefd79f05011af91fff14a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Mon, 19 Mar 2018 19:13:48 +0100
Subject: [PATCH] Do not depend on the initializing ellipsoid

---
 src/map/albersequal.cpp        |  9 +++++----
 src/map/albersequal.h          |  3 +--
 src/map/transversemercator.cpp | 23 ++++++++++++-----------
 src/map/transversemercator.h   |  2 +-
 4 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/src/map/albersequal.cpp b/src/map/albersequal.cpp
index cedde0d4..d4447c68 100644
--- a/src/map/albersequal.cpp
+++ b/src/map/albersequal.cpp
@@ -70,7 +70,6 @@ AlbersEqual::AlbersEqual(const Ellipsoid *ellipsoid, double standardParallel1,
 	double sp1, sp2;
 
 
-	_e = ellipsoid;
 	_latitudeOrigin = deg2rad(latitudeOrigin);
 	_longitudeOrigin = deg2rad(longitudeOrigin);
 	_falseEasting = falseEasting;
@@ -79,7 +78,9 @@ AlbersEqual::AlbersEqual(const Ellipsoid *ellipsoid, double standardParallel1,
 	sp1 = deg2rad(standardParallel1);
 	sp2 = deg2rad(standardParallel2);
 
-	_es2 = 2 * _e->flattening() - _e->flattening() * _e->flattening();
+	_a2 = ellipsoid->radius() * ellipsoid->radius();
+	_es2 = 2 * ellipsoid->flattening() - ellipsoid->flattening()
+	  * ellipsoid->flattening();
 	_es = sqrt(_es2);
 	_one_minus_es2 = 1 - _es2;
 	_two_es = 2 * _es;
@@ -109,7 +110,7 @@ AlbersEqual::AlbersEqual(const Ellipsoid *ellipsoid, double standardParallel1,
 		_n = sin_lat1;
 
 	_C = sqr_m1 + _n * q1;
-	_a_over_n = _e->radius() / _n;
+	_a_over_n = ellipsoid->radius() / _n;
 	nq0 = _n * q0;
 	_rho0 = (_C < nq0) ? 0 : _a_over_n * sqrt(_C - nq0);
 }
@@ -172,7 +173,7 @@ Coordinates AlbersEqual::xy2ll(const QPointF &p) const
 	if (rho != 0.0)
 		theta = atan2(dx, rho0_minus_dy);
 	rho_n = rho * _n;
-	q = (_C - (rho_n * rho_n) / (_e->radius() * _e->radius())) / _n;
+	q = (_C - (rho_n * rho_n) / _a2) / _n;
 	qc = 1 - ((_one_minus_es2) / (_two_es)) * log((1.0 - _es) / (1.0 + _es));
 	if (fabs(fabs(qc) - fabs(q)) > 1.0e-6) {
 		q_over_2 = q / 2.0;
diff --git a/src/map/albersequal.h b/src/map/albersequal.h
index fb6af6b0..3842f05b 100644
--- a/src/map/albersequal.h
+++ b/src/map/albersequal.h
@@ -18,13 +18,12 @@ public:
 	virtual Coordinates xy2ll(const QPointF &p) const;
 
 private:
-	const Ellipsoid *_e;
-
 	double _latitudeOrigin;
 	double _longitudeOrigin;
 	double _falseEasting;
 	double _falseNorthing;
 
+	double _a2;
 	double _rho0;
 	double _C;
 	double _n;
diff --git a/src/map/transversemercator.cpp b/src/map/transversemercator.cpp
index a6ae85a0..b276d3a4 100644
--- a/src/map/transversemercator.cpp
+++ b/src/map/transversemercator.cpp
@@ -47,14 +47,14 @@ Defense.
 
 
 #define SPHSN(lat) \
-	((double)(_e->radius() / sqrt(1.e0 - _es * pow(sin(lat), 2))))
+	((double)(_a / sqrt(1.e0 - _es * pow(sin(lat), 2))))
 #define SPHTMD(lat) \
 	((double)(_ap * lat - _bp * sin(2.e0 * lat) + _cp * sin(4.e0 * lat) \
 	  - _dp * sin(6.e0 * lat) + _ep * sin(8.e0 * lat)))
 #define DENOM(lat) \
 	((double)(sqrt(1.e0 - _es * pow(sin(lat),2))))
 #define SPHSR(lat) \
-	((double)(_e->radius() * (1.e0 - _es) / pow(DENOM(lat), 3)))
+	((double)(_a * (1.e0 - _es) / pow(DENOM(lat), 3)))
 
 
 TransverseMercator::TransverseMercator(const Ellipsoid *ellipsoid,
@@ -65,31 +65,32 @@ TransverseMercator::TransverseMercator(const Ellipsoid *ellipsoid,
 	double b;
 
 
-	_e = ellipsoid;
+	_a = ellipsoid->radius();
 	_longitudeOrigin = deg2rad(longitudeOrigin);
 	_latitudeOrigin = deg2rad(latitudeOrigin);
 	_scale = scale;
 	_falseEasting = falseEasting;
 	_falseNorthing = falseNorthing;
 
-	_es = 2 * _e->flattening() - _e->flattening() * _e->flattening();
+	_es = 2 * ellipsoid->flattening() - ellipsoid->flattening()
+	  * ellipsoid->flattening();
 	_ebs = (1 / (1 - _es)) - 1;
 
-	b = _e->radius() * (1 - _e->flattening());
+	b = _a * (1 - ellipsoid->flattening());
 
-	tn = (_e->radius() - b) / (_e->radius() + b);
+	tn = (_a - b) / (_a + b);
 	tn2 = tn * tn;
 	tn3 = tn2 * tn;
 	tn4 = tn3 * tn;
 	tn5 = tn4 * tn;
 
-	_ap = _e->radius() * (1.e0 - tn + 5.e0 * (tn2 - tn3) / 4.e0 + 81.e0
+	_ap = _a * (1.e0 - tn + 5.e0 * (tn2 - tn3) / 4.e0 + 81.e0
 	  * (tn4 - tn5) / 64.e0);
-	_bp = 3.e0 * _e->radius() * (tn - tn2 + 7.e0 * (tn3 - tn4) / 8.e0 + 55.e0
+	_bp = 3.e0 * _a * (tn - tn2 + 7.e0 * (tn3 - tn4) / 8.e0 + 55.e0
 	  * tn5 / 64.e0 ) / 2.e0;
-	_cp = 15.e0 * _e->radius() * (tn2 - tn3 + 3.e0 * (tn4 - tn5 ) / 4.e0) / 16.0;
-	_dp = 35.e0 * _e->radius() * (tn3 - tn4 + 11.e0 * tn5 / 16.e0) / 48.e0;
-	_ep = 315.e0 * _e->radius() * (tn4 - tn5) / 512.e0;
+	_cp = 15.e0 * _a * (tn2 - tn3 + 3.e0 * (tn4 - tn5 ) / 4.e0) / 16.0;
+	_dp = 35.e0 * _a * (tn3 - tn4 + 11.e0 * tn5 / 16.e0) / 48.e0;
+	_ep = 315.e0 * _a * (tn4 - tn5) / 512.e0;
 }
 
 QPointF TransverseMercator::ll2xy(const Coordinates &c) const
diff --git a/src/map/transversemercator.h b/src/map/transversemercator.h
index 1c11f319..35ce0a45 100644
--- a/src/map/transversemercator.h
+++ b/src/map/transversemercator.h
@@ -18,12 +18,12 @@ public:
 	virtual Coordinates xy2ll(const QPointF &p) const;
 
 private:
-	const Ellipsoid *_e;
 	double _longitudeOrigin;
 	double _latitudeOrigin;
 	double _scale;
 	double _falseEasting;
 	double _falseNorthing;
+	double _a;
 
 	double _es;
 	double _ebs;