Decode result not correct for negative values.

[GoogleCodeExporter]

What steps will reproduce the problem?
1.
        double lat = -77.9614596407155;
        double lon = -139.96324813171648;
2. try to encode this to a string
3. try to decode the string to lat & lon

What is the expected output? What do you see instead?
The latter one is the difference.

-77.9614596407155:70.14700636267662
-139.96324813171648:-83.69167774915695

What version of the product are you using? On what operating system?
Vista/JDK 1.6

Please provide any additional information below.

Test code:

    @Test
    public void testEncode_Accuracy_Mistake() {
        // -77.9614596407155:70.14700636267662
        // -139.96324813171648:-83.69167774915695
        double lat = -77.9614596407155;
        double lon = -139.96324813171648;

        String geohash = geohashUtil.encode(lat, lon);
        Assert.assertNotNull(geohash);

        double[] result = geohashUtil.decode(geohash);
        if (Math.abs(lat - result[0]) > 0.00001
                || Math.abs(lon - result[1]) > 0.00001) {
            System.out.println("============");
            System.out.println(lat + ":" + result[0]);
            System.out.println(lon + ":" + result[1]);
        }
    }

Original issue reported on code.google.com by cnhapp...@gmail.com on 9 Jun 2011 at 3:54