Changes between Version 4 and Version 5 of TutorialKMlCoordinates

Timestamp:

07/20/09 14:19:02 (4 years ago)

Author:

Wuaast

Comment:

--

TutorialKMlCoordinates

@@ -2 +2 @@
 
 I am going to explain (a) how to retrieve (and print) coordinates of all spatial features in a feature collection, and (b) how to find 
-the  nearest point compared to a given point. This tutorial presumes understanding of the Tutorial [wiki:TutorialKMlStreams Parsing KML into the Feature Model]. It also helps to have some basic knowledge about the [http://www.vividsolutions.com/jts/jtshome.htm Java Topology Suite (JTS)] and the concept of [http://en.wikipedia.org/wiki/Great-circle_distance Geodetic (Great Circle) Distances]. 
+the  nearest point out of a list of features compared to a given point. This tutorial presumes understanding of the Tutorial [wiki:TutorialKMlStreams Parsing KML into the Feature Model]. It also helps to have some basic knowledge about the [http://www.vividsolutions.com/jts/jtshome.htm Java Topology Suite (JTS)] and the concept of [http://en.wikipedia.org/wiki/Great-circle_distance Geodetic (Great Circle) Distances]. 
 
 === Getting the coordinates ===
@@ -24 +24 @@
 {{{
 GeometryFactory geomFactory = new GeometryFactory(new PrecisionModel(PrecisionModel.FLOATING), 4326);
+
+//com.vividsolutions.jts.geom.Point givenPoint = geomFactory.createPoint(...)
+
 double shortestDistance = Double.MAX_VALUE;
+Point nearestPoint = null;
+Point actualPoint = null;
+                
 for(Feature f : features.listFeaturesRecursively()){
         Geometry geom = f.getGeometry();
-        Point givenPoint = ...; // comes from somewhere else
-
         Coordinate[] coordinates = geom.getCoordinates();
         for (int i = 0; i < coordinates.length; i++) {
-                System.out.println(coordinates[i].x+" "+coordinates[i].y);
-                Coordinate[] current = {givenCoordinate, coordinates[i]}; // where does givenCoordinate come from 
-                if (new GeodeticDistance().length(geomFactory.createGeometry(current)) < shortestDistance) { 
-// changed to createGeometry, since we don't know what type we have here
-// it should not be length, but a distance between two geometries
-                        shortestDistance = new GeodeticDistance().length(geomFactory.createLineString(actualLine)); // again, should be createGeometry
-                        nearestPoint = new Point(coordinates[i].x, coordinates[i].y);
+                actualPoint = geomFactory.createPoint(coordinates[i]);
+                if (new GeodeticDistance().betweenGeometries(givenPoint, actualPoint)<shortestDistance) {
+                        shortestDistance = new GeodeticDistance().betweenGeometries(givenPoint, actualPoint);
+                        nearestPoint = actualPoint;
                 }
         }