[mkgmap-dev] [PATCH] --ignore-builtin-relations

Fri Aug 26 18:02:53 BST 2011

> On Thu, Aug 25, 2011 at 11:43:06PM +0200, WanMil wrote:
>> I think I am wrong?!?
>> You want to have some relation processing in the relations style file,
>> correct?
>
> Right. I would like to disable the built-in (non-style-file) processing
> of relations when creating auxiliary map layers, meant to be enabled or
> disabled on the device as needed. I have defined a number of routes-*
> styles for highlighting various route relations. Typically, you would
> not want to display all types of routes at the same time. For example,
> it is not likely to be useful to display bus and bicycle routes at the
> same time.
>
> I think that the turn restrictions only need to be processed for the
> layer(s) that are used for routing. Or, in other words, the absence of
> --route or --net should imply --ignore-turn-restrictions.

Sounds reasonable although I think it does not make a noticable 
difference. But if turn restrictions are not processed the tags used for 
it need not be loaded. Maybe that's a noticable improvement. One should 
test it.

Compare processing time:
1. Compile a map without --route or --net with the CVS version
2. Compile the same map but remove the turn-restrictions tag from the 
builtin-tag-list file.
The tags to remove are:
restriction
except
exception

>
>> But what do you think of the idea to check if there is any polygon
>> rule? Mmh, this is also not a 100% idea. The mp processing creates ways
>> tagged with the mp tags so that they can be processed by the ways file.
>> Example: you want to draw the borders of boundaries. So there will be
>> no polygon rule if someone wants to create a border layer but the
>> multipolygon processing is still required.
>
> Right, I was thinking roughly along the same lines.
>
> I am not sure, but would it be possible to skip the multipolygon
> processing of type=boundary relations when you only want to draw
> boundary lines (no polygons)?

I don't think so. I am not up2date what the latest recommendations in 
the wiki are but if the boundaries follow the multipolygon rules the 
ways itself should not be tagged (although it is tolerated and mostly 
done). So without the mp processing you get lots of ways without any tags.

I give an exmaple for another:
http://www.openstreetmap.org/browse/way/27503381
It is tagged with
admin_level = 7
boundary = administrative

but is a member of 4 boundaries (2 x 7 and 2 x 8). So in the end you get 
4 lines with distinct border information but only if multipolygons are 
processed.
Maybe you can do that with the relations style file too? I don't know.

>
>> Ok, so I have no more objections against committing. Could you please
>> add some more description what the option is for? And maybe a warning
>> hint and/or an example when it is a good or a bad choice to use it?
>
> OK, I will extend the help file description if we go along this route.
>
> In other news, there are more and more boundaries being defined for
> Finland. I think I will soon have to switch to --index and generating
> the map with MapSource. Currently, I am using mkgmap r2001, so that I
> get the half-broken way search with reasonable city names. After r2008
> (the branches/location merge) without --index, all streets seem to be
> assigned to one town (Nurmijärvi), even though the boundaries are valid.

r2001 is from the locator branch, isn't it? Is there any special reason 
why you use the locator branch without --index? There should be no 
advantage to the trunk without --index.

>
> 	Marko

WanMil