[mkgmap-dev] How to create a map covering Fiji & Samoa?

Sun Mar 4 14:01:18 GMT 2012

Hi Colin,

your are right, it's not the IDL, but the 180-degree longitude.

splitter and mkgmap are internally using integer values to represent the 
latitude and longitude values.
Longitude -180 is represented by -8388608, and +180 is reprensented by
8388608.
So, the integer values are very different, but -180 and +180 are - afaik -
exactly the same.
A lot of comparison are done with something like 
if (lat > maxlat)...
and I think a lot of them will fail.

Gerd

Colin Smale-2 wrote
> 
> Gerd,
> 
> I have no idea how to answer your question, but I was wondering if it is 
> really connected to the IDL or the 180-degree longitude? Of course 
> 179.99 East is separated from 179.99 West by only 0.02 degrees, not 
> 359.98. I can imagine how this would need some special handling. The IDL 
> wanders around quite a bit, roughly centred on 180. If the issue really 
> is connected to the IDL, I would love to learn how!
> 
> Colin
> 
> On 04/03/2012 11:09, GerdP wrote:
>> Hi,
>>
>> while optimizing splitter and mkgmap I did never see special code to
>> handle bounding boxes that cover the date limit.
>> I wonder if I have to test that case?
>>
>> In other words: What are the steps to create
>> a map covering e.g. Fiji and Samoa?
>> Are features like routing expected to work?
>>
>> Gerd
>>
>>
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