diff --git a/src/map/imgmap.cpp b/src/map/imgmap.cpp
index 2db62d47..fc8dc4aa 100644
--- a/src/map/imgmap.cpp
+++ b/src/map/imgmap.cpp
@@ -141,6 +141,12 @@ int IMGMap::zoomOut()
 	return _zoom;
 }
 
+void IMGMap::setZoom(int zoom)
+{
+	_zoom = zoom;
+	updateTransform();
+}
+
 void IMGMap::updateTransform()
 {
 	double scale = (2.0 * M_PI * WGS84_RADIUS) / (1<<_zoom);;
diff --git a/src/map/imgmap.h b/src/map/imgmap.h
index b3c96f17..0c46419e 100644
--- a/src/map/imgmap.h
+++ b/src/map/imgmap.h
@@ -21,7 +21,7 @@ public:
 	QRectF bounds();
 
 	virtual int zoom() const {return _zoom;}
-	virtual void setZoom(int zoom) {_zoom = zoom;}
+	virtual void setZoom(int zoom);
 	virtual int zoomFit(const QSize &, const RectC &);
 	virtual int zoomIn();
 	virtual int zoomOut();