How to Plot (show) user location on Image? iOS

Question

So here is task i need to get done on iOS:

Show User's Current Location on an Image like this:

Yes, like this Image!

So few things one will notice as soon as one look at it. Its Tilted. It's headings are Off. You can see horizon..!

Lets say,

• I have location coordinates for corners of this image.
• I have angle at which this image is tilted. (e.g 50°)
• I have heading angle of the image. (e.g -170° North, which means its about 10° South-West, correct me if im wrong.)
• And i have Zoom level on which this image would have been zoomed if it was on Google Maps/Google Earth. (e.g 14 zoom level - out of 20)

But thats the task, i need to show users location on such images. Just like in "Google Earth".

Can anyone give me heads up to accomplish this task?

Thank you everyone. :)

Answer 1

I achieved the desired result by plotting the coordinate on a UIView and transform it using CATrasnform3D. These explanations also help, Explanation of Transformation Matrix in terms of Core Animation and Core Animation Programming Guide itself.

_graphic.transform = CGAffineTransformMakeRotation(-2.89724656);

CATransform3D rotatedTransform = _graphic.layer.transform;

rotatedTransform.m34 = 1.0 / 500;
rotatedTransform.m22 = -2;
rotatedTransform.m41 = 170;
rotatedTransform.m42 = 170;

rotatedTransform = 
CATransform3DRotate(rotatedTransform, 
                    51 * M_PI / 180.0f, 
                    1.0f, 
                    0.0f, 
                    0.0f);


_graphic.layer.transform = rotatedTransform;

[_graphic setNeedsDisplay];

Thank you all.

Answer 2

Given the information you have, sounds like you can use line-plane intersection to solve your problem.