Nutiteq SDK source

Projection.java

package com.nutiteq.projections;

import com.jhlabs.map.Point2D.Double;
import com.jhlabs.map.proj.ProjectionFactory;
import com.nutiteq.components.Bounds;
import com.nutiteq.components.ImmutableMapPos;
import com.nutiteq.components.MapPos;
import com.nutiteq.utils.Const;

public class Projection {

  private final com.jhlabs.map.proj.Projection projection;

  private float offsetX;
  private float offsetY;
  private float scaleX;
  private float scaleY;

  public Projection(String name, Bounds bounds) {
    projection = ProjectionFactory.getNamedPROJ4CoordinateSystem(name);
    calculateInternalTransform(bounds);
  }

  public Projection(String[] args, Bounds bounds) {
    projection = ProjectionFactory.fromPROJ4Specification(args);
    calculateInternalTransform(bounds);
  }

  private void calculateInternalTransform(Bounds bounds) {
    float width = bounds.right - bounds.left;
    float height = bounds.top - bounds.bottom;
    offsetX = -bounds.left - width / 2;
    offsetY = -bounds.bottom - height / 2;
    scaleX = Const.UNIT_SIZE * 2 / width;
    scaleY = Const.UNIT_SIZE * 2 / height;
  }

  public ImmutableMapPos fromWgs84(float lon, float lat) {
    com.jhlabs.map.Point2D.Double src = new Double(lon, lat);
    com.jhlabs.map.Point2D.Double dst = new Double();
    projection.transform(src, dst);
    return new ImmutableMapPos((float) dst.x, (float) dst.y);
  }

  public MapPos toWgs84(float x, float y) {
    com.jhlabs.map.Point2D.Double src = new Double(x, y);
    com.jhlabs.map.Point2D.Double dst = new Double();
    projection.inverseTransform(src, dst);
    return new MapPos((float) dst.x, (float) dst.y);
  }

  /**
   * No part of public API
   */
  public MapPos fromInternal(float x, float y) {
    return new MapPos(x / scaleX - offsetX, y / scaleY - offsetY);
  }

  /**
   * No part of public API
   */
  public ImmutableMapPos toInternal(float x, float y) {
    return new ImmutableMapPos((x + offsetX) * scaleX, (y + offsetY) * scaleY);
  }
  
  /**
   * No part of public API
   */
  public float[] internalTransformationMatrix(float x, float y, float z) {
    com.jhlabs.map.Point2D.Double src = new Double(x, y);
    com.jhlabs.map.Point2D.Double dst = new Double();
    projection.inverseTransform(src, dst);
    float scaleCoeff = (float) (1.0 / Math.cos(Math.toRadians(dst.y)));
    float scaleZ = Math.min(scaleX, scaleY); // both should be the same actually 
    float[] transform = new float[16];
    transform[0] = scaleX * scaleCoeff;
    transform[5] = scaleY * scaleCoeff;
    transform[10] = scaleZ * scaleCoeff;
    transform[12] = (x + offsetX) * scaleX;
    transform[13] = (y + offsetY) * scaleY;
    transform[14] = z * scaleZ;
    transform[15] = 1;
    return transform;
  }
  
  /* Name of projection, usually "EPSG:xxxx"
   * Should be redefined by each projection!
   */
  public String name() {
    return "NA";
  }

}