Interpolate timestamps of a track between first and last trackpoint

Signed-off-by: Rob Norris <rw_norris@hotmail.com>

diff --git a/src/viktrack.c b/src/viktrack.c
index 7c8b071a64de110df2e84ff9394c3ef02e604a65..48e556de1c416affab979265613c7d82041ce8a2 100644 (file)
--- a/src/viktrack.c
+++ b/src/viktrack.c
@@ -1614,6 +1614,53 @@ void vik_track_anonymize_times ( VikTrack *tr )
   }
 }
 
+/**
+ * vik_track_interpolate_times:
+ *
+ * Interpolate the timestamps between first and last trackpoint,
+ * so that the track is driven at equal speed, regardless of the
+ * distance between individual trackpoints.
+ *
+ * NB This will overwrite any existing trackpoint timestamps
+ */
+void vik_track_interpolate_times ( VikTrack *tr )
+{
+  gdouble tr_dist, cur_dist;
+  time_t tsdiff, tsfirst;
+
+  GList *iter;
+  iter = tr->trackpoints;
+
+  VikTrackpoint *tp = VIK_TRACKPOINT(iter->data);
+  if ( tp->has_timestamp ) {
+    tsfirst = tp->timestamp;
+
+    // Find the end of the track and the last timestamp
+    while ( iter->next ) {
+      iter = iter->next;
+    }
+    tp = VIK_TRACKPOINT(iter->data);
+    if ( tp->has_timestamp ) {
+      tsdiff = tp->timestamp - tsfirst;
+
+      tr_dist = vik_track_get_length_including_gaps ( tr );
+      cur_dist = 0.0;
+
+      if ( tr_dist > 0 ) {
+        iter = tr->trackpoints;
+        // Apply the calculated timestamp to all trackpoints except the first and last ones
+        while ( iter->next && iter->next->next ) {
+          iter = iter->next;
+          tp = VIK_TRACKPOINT(iter->data);
+          cur_dist += vik_coord_diff ( &(tp->coord), &(VIK_TRACKPOINT(iter->prev->data)->coord) );
+
+          tp->timestamp = (cur_dist / tr_dist) * tsdiff + tsfirst;
+          tp->has_timestamp = TRUE;
+        }
+      }
+    }
+  }
+}
 
 /**
  * vik_track_apply_dem_data:

diff --git a/src/viktrack.h b/src/viktrack.h
index d2de2a9bed0f2b0c0497b5180248e786dd012754..5a2ac4c1092793cb9797808593247a481ef58795 100644 (file)
--- a/src/viktrack.h
+++ b/src/viktrack.h
@@ -150,6 +150,7 @@ VikTrack *vik_track_unmarshall (guint8 *data, guint datalen);
 void vik_track_calculate_bounds ( VikTrack *trk );
 
 void vik_track_anonymize_times ( VikTrack *tr );
+void vik_track_interpolate_times ( VikTrack *tr );
 gulong vik_track_apply_dem_data ( VikTrack *tr, gboolean skip_existing );
 void vik_track_apply_dem_data_last_trackpoint ( VikTrack *tr );
 gulong vik_track_smooth_missing_elevation_data ( VikTrack *tr, gboolean flat );

diff --git a/src/viktrwlayer.c b/src/viktrwlayer.c
index db4be26059d2205a63cdd29f808a5e22e710391f..4ba4b0ce9df1dd12cebb51da9874222b9cbd797a 100644 (file)
--- a/src/viktrwlayer.c
+++ b/src/viktrwlayer.c
@@ -5367,6 +5367,19 @@ static void trw_layer_anonymize_times ( menu_array_sublayer values )
     vik_track_anonymize_times ( track );
 }
 
+static void trw_layer_interpolate_times ( menu_array_sublayer values )
+{
+  VikTrwLayer *vtl = (VikTrwLayer *)values[MA_VTL];
+  VikTrack *track;
+  if ( GPOINTER_TO_INT (values[MA_SUBTYPE]) == VIK_TRW_LAYER_SUBLAYER_ROUTE )
+    track = (VikTrack *) g_hash_table_lookup ( vtl->routes, values[MA_SUBLAYER_ID] );
+  else
+    track = (VikTrack *) g_hash_table_lookup ( vtl->tracks, values[MA_SUBLAYER_ID] );
+
+  if ( track )
+    vik_track_interpolate_times ( track );
+}
+
 static void trw_layer_extend_track_end ( menu_array_sublayer values )
 {
   VikTrwLayer *vtl = VIK_TRW_LAYER(values[MA_VTL]);
@@ -8501,13 +8514,19 @@ static gboolean trw_layer_sublayer_add_menu_items ( VikTrwLayer *l, GtkMenu *men
     gtk_menu_shell_append ( GTK_MENU_SHELL(transform_submenu), item );
     gtk_widget_show ( item );
 
-    // Routes don't have timestamps - so this is only available for tracks
+    // Routes don't have timestamps - so these are only available for tracks
     if ( subtype == VIK_TRW_LAYER_SUBLAYER_TRACK ) {
       item = gtk_image_menu_item_new_with_mnemonic ( _("_Anonymize Times") );
       g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(trw_layer_anonymize_times), pass_along );
       gtk_menu_shell_append ( GTK_MENU_SHELL(transform_submenu), item );
       gtk_widget_set_tooltip_text (item, _("Shift timestamps to a relative offset from 1901-01-01"));
       gtk_widget_show ( item );
+
+      item = gtk_image_menu_item_new_with_mnemonic ( _("_Interpolate Times") );
+      g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(trw_layer_interpolate_times), pass_along );
+      gtk_menu_shell_append ( GTK_MENU_SHELL(transform_submenu), item );
+      gtk_widget_set_tooltip_text (item, _("Reset trackpoint timestamps between the first and last points such that track is traveled at equal speed"));
+      gtk_widget_show ( item );
     }
 
     if ( subtype == VIK_TRW_LAYER_SUBLAYER_TRACK )