altoslib: Allow gps time later than requested if it's first

When generating a KML file, we want to position markers near the start
of the flight section. This is done by looking for a GPS coordinate
'before' the starting point of the flight, which doesn't work well
when the first GPS coordinate is later than that. Pick the first point
after the chosen time if there isn't an earlier one.

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

diff --git a/altoslib/AltosFlightSeries.java b/altoslib/AltosFlightSeries.java
index 02bf64ff9772520b8e37d1aec713bce6c87734e5..2eaf80330d4d4b6b8b6c087981e0da599d1c6824 100644 (file)
--- a/altoslib/AltosFlightSeries.java
+++ b/altoslib/AltosFlightSeries.java
@@ -489,13 +489,24 @@ public class AltosFlightSeries extends AltosDataListener {
        public ArrayList<AltosGPSTimeValue> gps_series;
 
        public AltosGPS gps_before(double time) {
-               AltosGPS gps = null;
-               for (AltosGPSTimeValue gtv : gps_series)
-                       if (gtv.time <= time)
-                               gps = gtv.gps;
-                       else
-                               break;
-               return gps;
+               AltosGPSTimeValue nearest = null;
+               for (AltosGPSTimeValue gtv : gps_series) {
+                       if (nearest == null)
+                               nearest = gtv;
+                       else {
+                               if (gtv.time <= time) {
+                                       if (nearest.time <= time && gtv.time > nearest.time)
+                                               nearest = gtv;
+                               } else {
+                                       if (nearest.time > time && gtv.time < nearest.time)
+                                               nearest = gtv;
+                               }
+                       }
+               }
+               if (nearest != null)
+                       return nearest.gps;
+               else
+                       return null;
        }
 
        public AltosTimeSeries  sats_in_view;