[mkgmap-dev] [PATCH v1] Further reduction of the builtin-tag-list

Thu Oct 20 16:29:32 BST 2011

> On Wed, Oct 19, 2011 at 11:01:53PM +0200, Felix Hartmann wrote:
>> I don't get the treatment... I'm currently using ignore-maxspeed option
>> but I reference maxspeed in my style-file. Need no hard set maxspeed,
>> but I'm happy with maxspeed for classifying wether a street is rural or
>> urban...
>
> As far as I understand, the list of tags not to ignore will be updated
> from the style file. The more attribute names your style has, the more
> attributes will be parsed.
>
> WanMil's patch is about the builtin-tags-list, about attributes that are
> internally handled by mkgmap, no matter what is in the style files. It
> feels reasonable to me.
>
> 	Marko

That's it.
The list of tags that should be loaded is calculated as:

Tags to load =
+ builtin-tag-list
+ tags referenced in the styles
+ tags referenced in one of the hooks
- tags in the delete-tags-file

A hook is an additonal function that can add tags to the list, e.g. 
RoutingHook adds tags "access", "bicycle", "carpool" etc. if the "route" 
option is set. The SeaGeneratorHook adds the natural tag if the 
generate-sea option is set.

If a tag is in the builtin-tag-list it is loaded no matter if it is 
really used or not. The patch changes that for the tags type and maxspeed.
The patch has an effect when the --ignore-maxspeed option is set and the 
maxspeed tag is not referenced in the style. The second tag type will 
not have a big effect because its usage beside relations is quite small.

WanMil