Don't write negative alts.

diff --git a/gpsutil.c b/gpsutil.c
index ae648d093f08cb95ba6adbc88a7dd747517e50b0..27d55563b170ca952b48e580ccdb74d1fcc7f422 100644 (file)
--- a/gpsutil.c
+++ b/gpsutil.c
@@ -124,7 +124,8 @@ gpsutil_disp(const waypoint *wpt)
                lat < 0.0 ? 'S' : 'N',
                fabs(lon),
                lon < 0.0 ? 'W' : 'E',
-               wpt->altitude == unknown_alt ? 0 : wpt->altitude,
+               ((wpt->altitude == unknown_alt) || 
+                (wpt->altitude < 0.0)) ? 0 : wpt->altitude,
                'm', 
                wpt->description ? tdesc : "",
                icon_token);