HX20V Compass: how to read it

[peener]

When GPS is switched on, a compass needle is displayed on the screen. Does anyone know how it works?

Do I have to hold the camera in a horizontal position to be able to interpret it correctly (like you would do with a regular compass)? If I do that, the red side of the compass needle is not pointing to the North. It does turn when I turn the camera in the horizontal plan, but it is not consistent.

When I hold the camera in vertical (shooting) position, I can't interpret the needle position and on top of that, the needle disappears after a second. So, I would think this is not the way to use it.

The Firmware update on the Sony site should resolve that problem (90° error in compass display is what it says). I have installed that but it didn't improve things.

I don't understand either how this directional information is stored in the Exif information of a picture.

[Mick2011]

Hi peneer

I'm not sure I understand the problem here – is the compass not working when you hold the camera in certain positions? Can you describe the issue in more detail?

GPS info is triangulated from satellite information and stored in the form of co-ordinates. Directional info is recorded as part of that data.

Mick

[peener]

When the GPS is switched there are 3 related icons on the display: a compass needle, a satelite and the signal strength bars. As long as I hold the camera display in a horizontal position, these icons are visible. When I turn the camera in vertical position (for taking a picture), these icons disappear. Not all the time though, they switch on and off. I don't know whether this is normal or not. Apparantly, the camera has a directional sensor that tells the processor the orientation towards the horizontal plane.

But my question is mainly about the way the compass needle should work. It doesn't point north.

I do understand your explanation about the triangulation and the way the camera could calculate the direction. This is how it's done in Car GPS systems. But if the camera is doing it the same way, I don't see how it can work, because while shooting a picture, I'm usually not moving. But I can be turning around my vertical axle and then the camera would not notice. And it does notice, because I see the needle moving. The problem is, that it is not correct.

I hope this makes things more clear.

[peener · Accepted solution]

It looks like the mistery has been resolved: right after the upgrade towards the latest firmware, the needle was still wrong. But tonight, while trying again, the red part of the needle consistently points to the North. So it works! Don't ask me why it didn't do that directly.

And what's more, it doesn't need to see the sattelites for that, because it also works indoors with no GPS reception. So there must be a magnetic sensor inside. You don't need to move.

But the GPS function needs to be switched on to have the needle displayed.

The best way is obviously to hold the camera horizontal to be able to interpret the needle direction. But it also works in vertical position, although the icons tend to dissappear all the time.

I haven't found how the information of direction is stored in the photos: Picasa doesn't show the direction information.

I haven't check either whether direction information is stored in the GPS Track log file.