position accuracy

[Jussi Kukkonen]

Jussi Kukkonen wrote:
> ... I'd also like a to add
> position accuracy to the API, something that'll give the applications
> some idea how to use and present the coordinates. I'm thinking int in
> meters would be fine (gpsd even has that available: "Horizontal position
> uncertainty", althoough I've yet to check if it actually is valid). For
> other backends we'll just have to pull a number out of thin air -- e.g.
> 20000m for hostip.

Whoops, this method seems to already exist (it's just not implemented by
any backend). I have a problem with it though:

> <method name="current_position_error">
>   <arg type="d" name="latitude_error" direction="out" /><!--Meters-->
>   <arg type="d" name="longitude_error" direction="out" /><!--Meters-->
>   <arg type="i" name="fix_type" direction="out"/>
> </method>

First, I can't imagine where lat and lon would have (meaningfully)
different errors... This is not available from gpsd as an example. Maybe
this was a mistake and the errors were meant to be for horizontal and
vertical?

Second, the return value "fix_type" is really gps-specific. I don't mind
the gps-specific parts of the position API (e.g. satellites_data,
satellites_in_view) too much when they're in their own methods, but I'm
not too fond of that "fix_type" there.


-jussi

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