[mkgmap-dev] errors in routing

Sun Aug 2 00:14:54 BST 2009

Clinton Gladstone wrote:
> On Aug 1, 2009, at 10:13, Garvan & maew wrote:
>
>   
>> I re-tested a sample I posted before with routing problems, except  
>> this time I converted the data to OSM format first, and it has the  
>> same problem with routing as I noted in a larger map, and as I  
>> explained above.
>>
>> In the attached sample, snip.osm, if is not possible to route from
>>
>> N13.10744 E100.92402
>>
>> To
>> N13.09385 E100.91529
>>
>> Without jumping all over the place (or any points points on these  
>> roads).
>>     
>
> I did a quick test on a map extract of Asia which I had previously  
> compiled. I noted no routing errors between these points.
>
> One thing I found suspicious is that you are routing over a motorway  
> with only one lane. The default style automatically adds a oneway  
> attribute to all motorways. Could this be related to your routing  
> problem?
>
> You may wish to try a style file with the "add oneway" statement  
> removed from the following line:
>
> highway=motorway {add oneway = yes; add bicycle = no; add foot = no }  
> [0x01 road_class=4 road_speed=6 resolution 12]
>
>   
Thanks for the tip about highways being one way, and for taking the time 
to look at the issue. I normally  use polish format so I did not think 
about the styles. However when I change the highway and highway_link to 
primary and primary_link the roads are no longer one way and I get the 
same error. I will attach the corrected sample to this post.

I joined roads with the same name and attributes when importing OSM data 
into Polish format, so the road lengths tend to be much longer in my 
data than in the original, making this issue more apparent. The 
unaltered data for Thailand is full of un-connected junctions so it is 
difficult to test.

I have the same error happening in five or six places, all associated 
with split roads. This sample is the smallest file I could make that 
shows the problem.

Garvan

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