[mkgmap-dev] Include the following patches into trunk -- Patch4 - decrease douglas peucker error

Wed Mar 2 23:40:32 GMT 2011


On 02.03.2011 20:54, Johann Gail wrote:
> Okay I've done some comparisons between the two approximations.
>> For polygons the old version is much better because the patched version
>> creates bad artifacts. For streets at resolution 23 (if used) to 21 I
>> prefer it too. At resolution 20 I am indifferent and cannot really
>> decide what is better. However from 19 to x the  approach as given by
>> the patch is far superior (drawing speed on GPS much higher, actually
>> using the normal DP filter maps become more or less unusable for
>> resolution 16,18 or 19 on etrex).
>>
>> Can someone see how this behaviour could be implemented for lines only
>> from resolution 20 or 19 downwards, while keeping the current approach
>> of the DP filter for the rest?
>>
> Thanks for intensively testing my old patches and the propose for them 
> being checked in.
> Glad to see them work fine and beeing useful. :-)
>
> I have looked at this patch again. I think your proposal of switching 
> between them at a given resolution is a good one. This should preserve 
> the accuracy at higher zooms and compress the data at lower zooms. 
> Should be worth a try.
>
> I'm sorry, but at the moment I have no toolchain ready for compiling 
> mkgmap and preparing patches. If I find the time, I will look into it 
> the next days.
>
Okay great. Hope it's not too difficult to change the behaviour to get 
the best of both. I think actually at resolution 20, the "straight" 
patched behaviour should already be used for all lines.
> Regards,
> Johann
>
>