Use nm units in builtins.gie. Remove backward looking comments in code.

4 files changed, 18 insertions, 16 deletions

diff --git a/src/phi2.cpp b/src/phi2.cpp
index b9b37765..0fdca47c 100644
--- a/src/phi2.cpp
+++ b/src/phi2.cpp
@@ -116,6 +116,7 @@ double pj_phi2(projCtx ctx, const double ts0, const double e) {
    * Determine latitude angle phi-2.
    * Inputs:
    *   ts = exp(-psi) where psi is the isometric latitude (dimensionless)
+   *        this variable is defined in Snyder (1987), Eq. (7-10)
    *   e = eccentricity of the ellipsoid (dimensionless)
    * Output:
    *   phi = geographic latitude (radians)
@@ -123,13 +124,12 @@ double pj_phi2(projCtx ctx, const double ts0, const double e) {
    *   psi = log( tan(pi/4 + phi/2) *
    *              ( (1 - e*sin(phi)) / (1 + e*sin(phi)) )^(e/2) )
    *       = asinh(tan(phi)) - e * atanh(e * sin(phi))
+   *       = asinh(tan(chi))
+   *   chi = conformal latitude
    *
-   * OLD: This routine inverts this relation using the iterative scheme given
-   * by Snyder (1987), Eqs. (7-9) - (7-11).
+   * This routine converts t = exp(-psi) to
    *
-   * NEW: This routine converts t = exp(-psi) to
-   *
-   *   tau' = sinh(psi) = (1/t - t)/2
+   *   tau' = tan(chi) = sinh(psi) = (1/t - t)/2
    *
    * returns atan(sinpsi2tanphi(tau'))
    ***************************************************************************/
diff --git a/src/tsfn.cpp b/src/tsfn.cpp
index a0960a66..8ed258d6 100644
--- a/src/tsfn.cpp
+++ b/src/tsfn.cpp
@@ -11,10 +11,13 @@ double pj_tsfn(double phi, double sinphi, double e) {
    *   e = eccentricity of the ellipsoid (dimensionless)
    * Output:
    *   ts = exp(-psi) where psi is the isometric latitude (dimensionless)
+   *      = 1 / (tan(chi) + sec(chi))
    * Here isometric latitude is defined by
    *   psi = log( tan(pi/4 + phi/2) *
    *              ( (1 - e*sin(phi)) / (1 + e*sin(phi)) )^(e/2) )
    *       = asinh(tan(phi)) - e * atanh(e * sin(phi))
+   *       = asinh(tan(chi))
+   *   chi = conformal latitude
    ***************************************************************************/
 
     double cosphi = cos(phi);
diff --git a/test/gie/builtins.gie b/test/gie/builtins.gie
index 2432ccb0..1ec59b7a 100644
--- a/test/gie/builtins.gie
+++ b/test/gie/builtins.gie
@@ -1425,7 +1425,7 @@ expect  -0.001790143 -0.000895247
 -------------------------------------------------------------------------------
 operation +proj=etmerc   +ellps=GRS80
 -------------------------------------------------------------------------------
-tolerance 50e-9 m
+tolerance 50 nm
 accept  2 1
 expect  222650.796797586 110642.229411933
 accept  2 -1
@@ -3369,7 +3369,7 @@ operation +proj=merc   +ellps=GRS80
 tolerance 0 m
 accept  0 0
 expect  0 0
-tolerance 50e-9 m
+tolerance 50 nm
 accept  2 1
 expect  222638.981586547 110579.965218249
 accept  2 -1
@@ -3389,7 +3389,7 @@ direction inverse
 tolerance 0 m
 accept  0 0
 expect  0 0
-tolerance 50e-9 m
+tolerance 50 nm
 accept  200 100
 expect  0.00179663056824 0.00090436947704
 accept  200 -100
@@ -3413,7 +3413,7 @@ operation +proj=merc   +R=6400000
 tolerance 0 m
 accept  0 0
 expect  0 0
-tolerance 50e-9 m
+tolerance 50 nm
 accept  2 1
 expect  223402.144255274 111706.743574944
 accept  2 -1
@@ -3427,7 +3427,7 @@ direction inverse
 tolerance 0 m
 accept  0 0
 expect  0 0
-tolerance 50e-9 m
+tolerance 50 nm
 accept  200 100
 expect  0.00179049310978 0.00089524655486
 accept  200 -100
@@ -5700,7 +5700,7 @@ expect  -0.001790143 0.511651393
 -------------------------------------------------------------------------------
 operation +proj=tmerc   +ellps=GRS80
 -------------------------------------------------------------------------------
-tolerance 50e-9 m
+tolerance 50 nm
 accept  2 1
 expect  222650.796797586 110642.229411933
 accept  2 -1
diff --git a/test/unit/pj_phi2_test.cpp b/test/unit/pj_phi2_test.cpp
index f344a3d0..fdedae98 100644
--- a/test/unit/pj_phi2_test.cpp
+++ b/test/unit/pj_phi2_test.cpp
@@ -39,15 +39,14 @@ namespace {
 TEST(PjPhi2Test, Basic) {
     projCtx ctx = pj_get_default_ctx();
 
-    // Remove tests with |e| >= 1.  Expectation is that only sane values of e
-    // (and nan is here reckoned to be sane) are passed to pj_phi2.  Thus the
-    // return value with other values of e is "implementation dependent".
+    // Expectation is that only sane values of e (and nan is here reckoned to
+    // be sane) are passed to pj_phi2.  Thus the return value with other values
+    // of e is "implementation dependent".
 
     constexpr auto inf = std::numeric_limits<double>::infinity();
     constexpr auto nan = std::numeric_limits<double>::quiet_NaN();
 
-    // Use EXPECT_EQ instead of EXPECT_DOUBLE_EQ.  Strict equality is demanded
-    // here.
+    // Strict equality is demanded here.
     EXPECT_EQ( M_PI_2, pj_phi2(ctx, +0.0, 0.0));
     EXPECT_EQ(  0.0  , pj_phi2(ctx,  1.0, 0.0));
     EXPECT_EQ(-M_PI_2, pj_phi2(ctx,  inf, 0.0));