[Gta04-owner] Advance OpenStreetMap surveying with GTA04? / camera & heading

Christoph Mair christoph.mair at gmail.com
Mon Mar 19 08:35:52 CET 2012

On Sun, Mar 18, 2012 at 7:11 PM, Dr. H. Nikolaus Schaller
<hns at goldelico.com> wrote:
> Am 18.03.2012 um 19:01 schrieb Mayeul Kauffmann:
>> Thanks!
>> So for the moment camera does not work. 8-(
>> What about the heading? (including when device is in vertical position)
> There is a HMC5883L 3D compass chip inside. Maybe someone else
> can comment on the status of the kernel drivers.

AFAIK the driver is not yet includet in the gta04 kernel, but this is
a minor problem and can be fixed quite easily. The driver for the
accelerometer is also not yet included. You will need it to get
tilt-compensation. There exists a simple hack that reads the raw
acceleration values from the chip and delivers them to userspace using
a sysfs file, but it's not a real driver with a standardized
With these two chips working, you need a piece of software to
calculate the tilt compensated heading from the raw compass and
accelerometer readings. Maybe "valacompass"
(http://wiki.openmoko.org/wiki/ValaCompass) can be modified in order
to get the desired results.


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