[mkgmap-dev] Bug report --remove-short-arcs=5 ???

Tue Mar 2 12:54:44 GMT 2010

Mark Burton wrote:
> Hello Garvan,
>
>   
>> I found a generalize function in gpsmapedit that removed 10% of the 
>> points in the file, but the national boundaries still did not display, 
>> so I split the very long polyline up and then it compiled correctly. 
>>     
>
> I don't see why that was required because we already split lines that
> have more than 250 points.
>
>   
>> This experience may be worth noting for others who see long lines 
>> disappearing with no error message when compiling in osm format.
>>     
>
> Sure, but I would rather find out why the existing line splitting
> didn't work satisfactorily.
>
> Mark
>   
I managed to isolate the problem further.

The lines disappear only when you have ways where the first and last 
point of the way are identical. It makes no difference if I merge the 
first and last node or when they have separate node id's. This has 
allowed me to make a small file demonstrating the problem, which I have 
uploaded to http://dl.dropbox.com/u/4900023/cambodia.osm.gz .

This file contains nine ways (contour lines) but when compiled with the 
option --remove-short-arcs=5 only three ways (one of which might be too 
small to see) are in the img file.

Now that I understand the problem I can avoid it easily by 
pre-processing the file, but I am sure others must be relying on 
--remove-short-arcs with raw osm input.

Garvan