“(int)Math.ceil(double)” always return 1, even when the value is greater than 1

Question

I'm creating an Android app and I need to calculate the movement speed of the device. I do this by taking an average of some earlier locations' speeds.
However, I need the speed to be in km/h as an int , so I use

(int)Math.ceil(speedAsDouble)

However, this always equal to 1 , even if the speedAsDouble is 7.8825246 or 0.58178 .
This is the relevant part of the code:

// Create a variable for the speed
double speedAsDouble = 0d;

// Loop through the last points
for(int i = 0; i < lastPoints.size() - 1; i++)
{
    // Add the speed for the current point to the total speed
    speedAsDouble += (double)(lastPoints.get(i).distanceTo(lastPoints.get(i + 1)) / (lastPoints.get(i + 1).getTime() - lastPoints.get(i).getTime()));
}

// Divide the speed by the number of points
speedAsDouble /= (double)lastPoints.size();
// Convert the speed to km/h
speedAsDouble *= 3.6d;

// Log the speed
System.out.println("Speed: " + speedAsDouble);

I then round the number and cast it to an int as described above using

int speedAsInt = (int)Math.ceil(speedAsDouble)

and log the number again with

System.out.println("Rounded speed: " + speedAsInt)

Here is a part of the log:

05-17 12:00:42.605  24610-24610/package I/System.out﹕ Speed: 0.0
05-17 12:00:42.635  24610-24610/package I/System.out﹕ Rounded speed: 0
05-17 12:00:43.625  24610-24610/package I/System.out﹕ Speed: 7.026718463748694E-4
05-17 12:00:43.645  24610-24610/package I/System.out﹕ Rounded speed: 1
05-17 12:00:44.595  24610-24610/package I/System.out﹕ Speed: 5.27003884781152E-4
05-17 12:00:44.615  24610-24610/package I/System.out﹕ Rounded speed: 1
05-17 12:00:45.595  24610-24610/package I/System.out﹕ Speed: 4.216031078249216E-4
05-17 12:00:45.635  24610-24610/package I/System.out﹕ Rounded speed: 1
05-17 12:00:46.595  24610-24610/package I/System.out﹕ Speed: 0.002668234216980636
05-17 12:00:46.605  24610-24610/package I/System.out﹕ Rounded speed: 1

I've spent much time looking at this, trying different variable types and casting variables but with no success.

Answer 1

In all the outputs you printed (except the first one which is 0) Speed is smaller than 1 ( 7.026718463748694E-4 , 5.27003884781152E-4 , etc...). Notice the negative exponent.

Therefore it's no wonder ceil returns 1.

Answer 2

Please look more carefully at your output, for example:

05-17 12:00:43.625 24610-24610/package I/System.out﹕ Speed: 7.026718463748694E-4

doesn't mean you have 7.02, but 0.000702. There is E-4 at the end. When you would use ceil it will always return 1.