[OSM-talk] OSM maps on Garmin GPS

raphael Jacquot sxpert at sxpert.org
Tue Nov 21 16:18:30 GMT 2006


SteveC wrote:
> * @ 21/11/06 02:12:10 PM schuyler at nocat.net wrote:
>> * On 21-Nov-2006 at  5:32AM PST, raphael Jacquot said:
>>>> You make it sound like magic.  What is the essential algorithm or 
>>>> data structure in PostGIS that causes this speed-up?  Could the 
>>>> same speed be achived with the GIS extensions to MySQL?  Could it 
>>>> be achieved by changing the old OSM tile generation code on top of 
>>>>
>>> simple...
>>> the r-tree based GIST index on bounding boxes that's applied on the 
>>> geometry column :D
>> MySQL 5.0 claims to support R-tree based spatial indexing:
>>
>>   http://dev.mysql.com/doc/refman/5.0/en/optimizing-spatial-analysis.html
>>
>> Haven't used it, so can't say how efficient it is. I've been in
>> favor of backing OSM with a proper spatial database from day one, so I
> 
> For any reason other than a hunch?
> 
> I thought nick hill disproved all this?
> 
> have fun,
> 
> SteveC steve at asklater.com http://www.asklater.com/steve/
> 

well, lets put it this way, necessity is the mother of invention.
if people came up with this, there must be a good reason, such as 
"yikes, it's faster".
what would have been the reason if it didn't give any advantage over the 
regular thing ?





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