backup commit, formerly hosted on now inaccessible CVS

NOTES

@@ -0,0 +1,74 @@
+
+
+GIOChannel* g_io_channel_unix_new           (int fd);
+g_io_channel_set_encoding() function with NULL
+GIOStatus   g_io_channel_set_encoding       (GIOChannel *channel,
+                                             const gchar *encoding,
+                                             GError **error);
+guint       g_io_add_watch                  (GIOChannel *channel,
+                                             GIOCondition condition,
+                                             GIOFunc func,
+                                             gpointer user_data);
+gboolean    (*GIOFunc)                      (GIOChannel *source,
+                                             GIOCondition condition,
+                                             gpointer data);
+	FALSE for end watch
+
+
+Distance Point To Line:
+(for Peuker)
+
+d = |v^^.r| =   (|(x_2-x_1)(y_1-y_0)-(x_1-x_0)(y_2-y_1)|)
+                /
+                (sqrt((x_2-x_1)^2+(y_2-y_1)^2))
+
+- Ausgleichskurve
+	Ausgleichsrechnung
+	Interpolation
+
+* Peuker line simplification
+* auto-split tracks
+	if track has "gaps" then split track into two tracks.
+	A gap is when in a group of four points A, B, C, D the distance
+	from A to B and C to D is about the same but B to C is "a lot" more.	
+* spike filter
+	calculate mean deviation of all points of one track, then
+	delete all points that have deviation > delta,
+	recalculate mean deviation and redo
+* mean of two tracks A, B
+	for each point of track A calculate distance to
+	track B and create a new point on a new track in the middle of the
+	distance. Next do the same process for all point of track B.
+	The new track lies in the middle between A and B.
+	Requires component-wise distance function with direction, i.e. e.g.
+	distance of point is x=-5 and y=3 to track.
+* merge of two tracks
+	for each point of track A find nearest corresponding point on
+	track B, then calculate the average between both points and record
+	this as new track point
+	Repeat this for each point of track B.
+	Limit the averaging to a maximum distance.
+
+
+SQLite tables
+-------------
+tracks		track headers (streets, boundaries, rivers, ...)
+	idx	pkey index
+	tid	track id, id common to all data points of one track
+	name	track-/streetname
+	ttype	track-/streettype
+	latmin	bbox latitude min
+	lonmin
+	latmax
+	lonmax
+trackpts	the actual track (all tracks combined in one table?)
+	lat
+	lon
+	ele
+	dtim
+	nrsat
+	hdop
+	vdop
+	pdop
+points		POIs
+cities		name, center location, "size"