Yves Goergen wrote:
> On 11.01.2009 02:15 CE(S)T, Chris Browet wrote:
>   
>> I envision to add an additional preferences tab with actions default.
>>     
>
>   
>> I plan to implement read-only layers for this kind of behaviour, where
>> the GPX layers can be made non-snapable as a whole.
>>     
>
> Third option candidate: Make track layers read-only by default?
>   
I'd appreciate that. But does it really prevent nodes from merging with 
track points? A read only track point can basically merged with a moving 
node (making the track point's position the new one).
>>     - I've been pretty surprised seeing my tracks beeing interrupted on
>>     straight high speed segments now. I finally found the option to change
>>     the distance to some higher value. I think the default value (100m?) is
>>     not useful or even that feature beeing activated by default is not
>>     useful. My Garmin device is configured at the highest possible track
>>     point rate (it is still interpolating).
>>     
>
> What is that rate, how many seconds does it wait for a new track point?
> Sounds like 5 seconds or more. Maybe the track splitting could be done
> by time, not by distance? Or by both. If delta_time > 1 minute and
> delta_position > 100 metres, then split the track. That should do well
> enough for both time-based and distance-based track recording. (I always
> record at 1 point per second and that gives me a huge number of points
> that tend to overlap in the display at walking speed... Hence that "GPX
> node zoom" patch...)
>
> It doesn't matter what the rate actually is. Garmin devices always try to 
> interpolate track points, which is basically ok. If you are driving a 
> straight line (in terms of accuracy), why storing additional track points if 
> two points are sufficient to define the line? You cannot disable that feature 
> in all Garmin handheld devices that I know. That's probably a relic of former 
> time with small internal memory. But it is actually ok since the primary 
> purpose these devices is not track recording.
> My point was that the default for this Merkaartor option is too short for 
> "normal" (Garmin) tracks. 
> Your proposal sounds good to me, taking the track time stamp into account. 
>   
Regards,

Peter

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