I am building an Android application based on Augmented Reality. The main idea is when user opens up my application, by default device’s camera starts in preview mode. Based on user’s current GPS location and the direction in which user/camera is facing I want to calculate which are the set of latitudes and longitudes in the range?
Following image explains my scenario very well. I have full set of latitudes and longitudes as drawn all black spots in the figure. Now suppose user is at the center of the circle. Also considering that he is viewing in North direction. If we consider an angle of 45 degree towards North direction. I want to get set of latitudes and longitudes which are coming in this 45 degree viewable area.
I am able to get the direction in which user’s camera is facing. I am also able to find user’s current GPS location. I have full set of latitudes and longitudes stored in my SQLite database. Now I want to calculate is the set of latitudes and longitudes in which user’s device camera is facing.
I hope I have explained pretty well here. Its bit urgent if anyone can help on this.
Thanks in advance.
To obtain the viewing angle, you can use as an approximation the Camera.Parameters getHorizontalViewAngle() method. Let’s call it alpha. You also know the bearing of your device from its point of view to magnetic North, let’s call it beta.
From there, within a given radius, iterate through set of database locations, compute the bearing from your position to its, and check if it is inside the interval [beta-alpha/2, beta+alpha/2]
If you’re not really on a rush into this, I would suggest to take a look into Mixare, its an open source framework which deals with location and AR.