[mkgmap-dev] Sea generation

Tue Nov 9 20:46:38 GMT 2010


On 09.11.2010 21:28, WanMil wrote:
>>
>>
>> On 04.11.2010 19:52, WanMil wrote:
>>> Hi all,
>>>
>>> I have started to rework the sea generation code. There have been
>>> several reports of problems with flooded tiles in the last weeks so I
>>> think it is neccessary to improve some parts of it.
>>>
>>> The first thing I've started is to implement a flooded tile blocker. 
>>> The
>>> algorithm has been discussed a while ago on this list. It uses a
>>> quadtree implementation which is able to return all points contained by
>>> a polygon. The quadtree is filled with all highway points. If a sea
>>> polygon contains too many points that belong to highways something is
>>> wrong and the sea polygon is discarded.
>>>
>> Are you still working on the flooded tile blocker?
>
> Yes. It will take some time until I can publish a first version but I 
> will definitely try to implement it.
>
>>
>> I think that even with external coastline bits and pieces - above code
>> should be implemented (or it would be great...).
>>
>> Else one will need for more or less any country (at least) an external
>> coastline file....
>> Also sometimes large lakes flood a whole tile....
>
> The tile blocker will only be one improvement. The extra coastline 
> input files will uss the normal sea generation process. So all 
> improvements to this will improve both ways of generating the sea.
Great. I just noticed on last Europe extract. I had no tile flooded 
touching the coastline, but three tiles flooded inside the main 
countryside....
So if we don't want to loose large lakes that also get tagged with 
coastline, we will need an at least primitive check for flooded tiles...
>
> WanMil