[mkgmap-dev] [PATCH v2] Black/Whitelist

Tue Jan 5 23:34:50 GMT 2010

On 06.01.2010 00:26, Johann Gail wrote:
>    
>>>> Could someone please commit or deny the patch. It is open for a long
>>>> time, no one has complained about it and I think it's a useful
>>>> enhancement.
>>>>
>>>>
>>>>          
>>> Sorry, I don't see the use of a black/whitelist of tags.
>>> The information of used tags should be contained in the style files, so
>>> why should I have to manage another additional file?
>>> Is it for speed/resource reasons?
>>>
>>> Regards,
>>> Johann
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>>>
>>>
>>>        
>> Johann,
>>
>> yes it speeds up the map generation by magnitude of times in case the
>> map uses only very few parameters. e.g. if you want to create a map that
>> visualizes the maxspeed (or maxheight, maxweight....) tag only its
>> useless to parse all other parameters.
>>
>> You are right that this information is also contained in the style files
>> and in future a better patch should automatically compile this
>> information from the style files.
>>
>> WanMil
>>
>>
>>      
> I'm not really inside the style code, so I don't completely understand
> the background of this.
>
> But in my understanding the osm data has to be parsed from beginning to
> end. Before I can decide to dismiss an parameter, I have to read it in
> and parse it, haven't I ? If there is no action defined in the style
> file, no style rule is active and nothing else should be happening. So
> why handle it with extra code?
>
> In my personal opinion I don't like another (superfluous) file,
> especially the blacklist file. And the whitelist *IS* the style file. No
> entrys here means no action!
>
> But as I said, style file is not really my part. And i believe you, that
> it speeds up the process.
>
> Regards,
> Johann
>    
The blacklist is for example needed if you want to get rid of all 
motorcar=no tags, because you want to use motorcar/motorcycle mode for 
bicycle routing. Otherwise these tags will be be enacted.
This is not easily doable inside the style-file (as action rules are 
limited on one action rule per way id, deleting these tags via action 
rule will be very very complicated).

The reason is, that there is a lot more about the maps, that is not 
influencable via the style-file. I don't need a white-list, but I am 
sure it will make great speed improvments if you want to layer your map 
(e.g. sea layer). Automatically generating a white-list would of course 
be great if speed improvments can be made - however the whitelist would 
have to be (in any case or intelligently based on things like if there 
is a line with road_speed road_class) appended to access tags.
Actually would one have to add name=* to the whitelist in order to have 
names??? Or ref=*? --- or are some keys included by default?

Here is my blacklist that I'm currently using (well still using delete 
tags option):

motorcar=no
motorcar=private
motorcycle=no
motorcycle=private
hgv=no
hgv=private
psv=no
psv=private
taxi=no
taxi=private
emergency=no
emergency=private
delivery=no
delivery=private
goods=no
goods=private

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