adjust greatcircle conversion factors, kill gcgeodist cheat. (#1156)

* tweak greatcircle conversions.

* modify arc-project test to use microdegrees instead of nanodegrees.

* kill unused metric prefix conversion macros.

Author: tsteven4

defs.h

@@ -115,11 +115,6 @@ constexpr double MPH_TO_MPS(double a) { return a * kMPSPerMPH;}
 /* knots(nautical miles/hour) to meters/second */
 constexpr double KNOTS_TO_MPS(double a)  {return a * kMPSPerKnot;}
 
-#define MILLI_TO_MICRO(t) ((t) * 1000)  /* Milliseconds to Microseconds */
-#define MICRO_TO_MILLI(t) ((t) / 1000)  /* Microseconds to Milliseconds*/
-#define CENTI_TO_MICRO(t) ((t) * 10000) /* Centiseconds to Microseconds */
-#define MICRO_TO_CENTI(t) ((t) / 10000) /* Centiseconds to Microseconds */
-
 constexpr int kDatumOSGB36 = 86; // GPS_Lookup_Datum_Index("OSGB36")
 constexpr int kDautmWGS84 = 118; // GPS_Lookup_Datum_Index("WGS 84")
 

grtcirc.h

@@ -45,9 +45,11 @@ void linepart(double lat1, double lon1,
               double* reslat, double* reslon);
 
 /* Degrees to radians */
-constexpr double DEG(double x) { return (x) * 180.0 / M_PI; }
+constexpr double kDegreesPerRadian = 180.0 / M_PI;
+constexpr double DEG(double x) { return x * kDegreesPerRadian; }
 
 /* Radians to degrees */
-constexpr double RAD(double x) { return (x) * M_PI / 180.0; }
+constexpr double kRadiansPerDegree = 1.0 / kDegreesPerRadian;
+constexpr double RAD(double x) { return x * kRadiansPerDegree; }
 
 #endif

reference/arc-project1.csv

@@ -0,0 +1,3 @@
+No,Latitude,Longitude,Name,Symbol
+1,28.356662,-16.497183,"wpt2","flag, red"
+2,28.357407,-16.501378,"wpt3","flag, green"

reference/arc-project1.gpx

@@ -0,0 +1,5 @@
+No,Latitude,Longitude,Name,Symbol
+1,28.358827,-16.501228,"wpt1","flag, green"
+2,28.354380,-16.495831,"wpt4","flag, green"
+3,28.353926,-16.496775,"wpt5","flag, green"
+4,28.358987,-16.499790,"wpt6","flag, green"