Convert pixel coordinate into map coordinate

Summary

Many user-interactive MapObjects Java applications need to get the location of mouse-click in the map. The location of a mouse-click can be returned from the MouseEvent object in terms of the Map object's pixel coordinate value. To perform various spatial functions, we need to convert this pixel coordinate into a map coordinate. This article outlines the steps to convert a pixel coordinate into a map coordinate.

Procedure

1. Get the x and y location from the MouseEvent e:
   
   

   Code:
   int x1=e.getX();
   int y1=e.getY();

   
   
   
2. Convert the integer values into double type:
   
   

   Code:
   double doubleX1=new Integer(x1).doubleValue();
   double doubleY1=new Integer(y1).doubleValue();

   
   
   
3. Create a point object in pixel units:
   
   

   Code:
   com.esri.mo.cs.geom.Point pixelPoint= new com.esri.mo.cs.geom.Point(doubleX1,doubleY1);

   
   
   
4. Get the Transform object from the Map and call the transform function:
   
   

   Code:
   com.esri.mo.cs.geom.Transform trans = map1.getPixelToWorldTransform();
   com.esri.mo.cs.geom.Point mapPoint= trans.transform(pixelPoint, null);

   
   
   
5. Get the x and y location in map coordinates from the transformed point:
   
   

   Code:
   double mapX=mapPoint.x;
   double mapY=mapPoint.Y
   

   
   
   

   Note:
   Call getWorldToPixelTransform function on map object to transform Map Coordinate to Pixel Coordinate.