Hello there,
Few weeks ago I reported a bug about closed contour lines. Someone
answered me that was an old error. I found the lost patch in the mailing
list and I tested it on a huge file. It works both for lines and polygons.
All the best to the dev team,
David
Index: src/uk/me/parabola/mkgmap/filters/DouglasPeuckerFilter.java
===================================================================
--- src/uk/me/parabola/mkgmap/filters/DouglasPeuckerFilter.java (revision 1061)
+++ src/uk/me/parabola/mkgmap/filters/DouglasPeuckerFilter.java (working copy)
@@ -28,7 +28,7 @@
*/
public class DouglasPeuckerFilter implements MapFilter {
- private static final double ERROR_DISTANCE = 5.4 / 2; //One unit is
5.4 m, so error dist is 2.6m
+ private static final double ERROR_DISTANCE = 5.4 / 8; //One unit is
5.4 m, so error dist is 0.65m
//Can be increased more, but may lead
to artifacts on T-crossings
private final double filterDistance;
private double maxErrorDistance;
@@ -51,6 +51,8 @@
* @param next This is used to pass the possibly transformed element
onward.
*/
public void doFilter(MapElement element, MapFilterChain next) {
+ boolean is_polygon = false;
+
// First off we don't touch things if at the highest level of
detail
if (resolution == 24) {
// XXX 24 is not necessarily the highest level.
@@ -64,13 +66,14 @@
int n = points.size()-1;
// Create a new list to rewrite the points into. Don't alter
the original one
- List<Coord> coords = new ArrayList<Coord>(n);
+ List<Coord> coords = new ArrayList<Coord>(n+1);
coords.addAll(points);
// If the first point is identic with the last one (a polygon),
drop it
// Otherwise douglasPeucker will not work!
while ((n > 0) && coords.get(0).equals(coords.get(n))) {
coords.remove(n);
+ is_polygon = true; // remember that the point was
removed for later
n--;
}
@@ -105,6 +108,10 @@
//#endif
MapLine newline = line.copy();
+ // If it was a polygon add the last point again that was
removed before the Douglas-Peucker algorithm
+ if (is_polygon)
+ coords.add(coords.get(0));
+
newline.setPoints(coords);
next.doFilter(newline);
}
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