How to plot current location in a Google Maps Image

Question

I want to create Android App with a still image map, [ custom map ]

in it.

1) current location google map image (screen short). [ it may be our won drawing..] as shown below.

9.94015,76.273953 is the location of the image.

In this image the blue plot indicates the current location.

How to do this?

Mercator can do this very easily, but I am very new in programming...

I can't do it.

If any body help me with a sample project I will appreciate it.

Answer 1

R u trying to do something like google map marker? If so then u need to use ItemizedOverlay. u will find examples on ItemizedOverlay on net. Just google it for "Examples on ItemizedOverlay".

Do u want to just draw a circle kind of shape on mapView?? If so then this is what u have to do.. Write a class that extends ItemizedOverlay...... In the onDraw method use this code

@Override

public void draw(Canvas canvas, MapView mapView, boolean shadow/*, long when*/) {

    super.draw(canvas, mapView, shadow);

    Paint paint = new Paint();
    // Converts lat/lng-Point to OUR coordinates on the screen.
    android.graphics.Point myScreenCoords = new android.graphics.Point();

    GeoPoint point = new GeoPoint(15340000,75120000);
    mapView.getProjection().toPixels(point, myScreenCoords);
    paint.setStrokeWidth(1);
    paint.setARGB(255, 255, 255, 255);
    paint.setStyle(Paint.Style.STROKE);

    paint.setTextSize(20);
    paint.setColor(Color.RED);
    paint.setStrokeWidth(2);


     canvas.drawText("Here I am...", myScreenCoords.x-10,myScreenCoords.y-48, paint);
    return true;                                                   }

Answer 2

If you know the map coordinates (left, right, top bottom), you can easily work out how much each pixel represents. Using this and the GPS lat long, just draw a circle at the correct pixel.

So for the X location: (this is not code)

Map left = 10 
Map Right = 15
Image Width = 1000 pixels

Therefore:

each pixel = (15-10)/ 1000
           = 0.005

You are at GPS X coordinate 11.5 So:

11.5 - 10 = 1.5
1.5 / 0.005 = 300

So you need to draw your circle at pixel 300 on the X axis, over your image.

Repeat for Y coordinate. (using height, top and bottom)