altoslib: Add range and elevation to AltosGreatCircle

Move the computations from AltosState here so they can be re-used elsewhere.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/altoslib/AltosGreatCircle.java b/altoslib/AltosGreatCircle.java
index 921356a59f0cc36ae9bfda643b8f300ea423a096..f1cf0ae9089173de180b9b0e39108379ed807a53 100644 (file)
--- a/altoslib/AltosGreatCircle.java
+++ b/altoslib/AltosGreatCircle.java
@@ -22,6 +22,8 @@ import java.lang.Math;
 public class AltosGreatCircle {
        public double   distance;
        public double   bearing;
+       public double   range;
+       public double   elevation;
 
        double sqr(double a) { return a * a; }
 
@@ -54,9 +56,8 @@ public class AltosGreatCircle {
                return bearing_string[length][(int)((bearing / 90 * 8 + 1) / 2)%16];
        }
 
-       public AltosGreatCircle (double start_lat, double start_lon,
-                                double end_lat, double end_lon)
-       {
+       public AltosGreatCircle (double start_lat, double start_lon, double start_alt,
+                                double end_lat, double end_lon, double end_alt) {
                double lat1 = rad * start_lat;
                double lon1 = rad * -start_lon;
                double lat2 = rad * end_lat;
@@ -88,14 +89,25 @@ public class AltosGreatCircle {
                }
                distance = d * earth_radius;
                bearing = course * 180/Math.PI;
+
+               double height_diff = end_alt - start_alt;
+               range = Math.sqrt(distance * distance + height_diff * height_diff);
+               elevation = Math.atan2(height_diff, distance) * 180 / Math.PI;
+       }
+
+       public AltosGreatCircle (double start_lat, double start_lon,
+                                double end_lat, double end_lon) {
+               this(start_lat, start_lon, 0, end_lat, end_lon, 0);
        }
 
        public AltosGreatCircle(AltosGPS start, AltosGPS end) {
-               this(start.lat, start.lon, end.lat, end.lon);
+               this(start.lat, start.lon, start.alt, end.lat, end.lon, end.alt);
        }
 
        public AltosGreatCircle() {
                distance = 0;
                bearing = 0;
+               range = 0;
+               elevation = 0;
        }
 }

diff --git a/altoslib/AltosState.java b/altoslib/AltosState.java
index f1bcb1c1a67a7e87ee5a3ef4cc70e1ce29c44351..a3b9a8c07efafdb54f889094c09e1b7ba6a505f9 100644 (file)
--- a/altoslib/AltosState.java
+++ b/altoslib/AltosState.java
@@ -248,23 +248,21 @@ public class AltosState {
 
                if (height != AltosRecord.MISSING && height > max_height)
                        max_height = height;
+               elevation = 0;
+               range = -1;
+               gps_height = 0;
                if (data.gps != null) {
                        if (gps == null || !gps.locked || data.gps.locked)
                                gps = data.gps;
                        if (ngps > 0 && gps.locked) {
-                               from_pad = new AltosGreatCircle(pad_lat, pad_lon, gps.lat, gps.lon);
-                       }
-               }
-               elevation = 0;
-               range = -1;
-               if (ngps > 0) {
-                       gps_height = gps.alt - pad_alt;
-                       if (from_pad != null) {
-                               elevation = Math.atan2(height, from_pad.distance) * 180 / Math.PI;
-                               range = Math.sqrt(height * height + from_pad.distance * from_pad.distance);
+                               double h = height;
+
+                               if (h == AltosRecord.MISSING) h = 0;
+                               from_pad = new AltosGreatCircle(pad_lat, pad_lon, 0, gps.lat, gps.lon, h);
+                               elevation = from_pad.elevation;
+                               range = from_pad.range;
+                               gps_height = gps.alt - pad_alt;
                        }
-               } else {
-                       gps_height = 0;
                }
        }