Thread: [Announce] modRana: a flexible GPS navigation system
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MartinK is offline MartinK
2012-03-14 , 15:54
Posts: 1,548 | Thanked: 7,510 times | Joined on Apr 2010 @ Czech Republic
#952
Originally Posted by jafd View Post
Yet another conclusion: it's a nice idea to pre-render some large chunks of the world at all zoom levels and distribute the resulting SQLite files. Shame no one has done it yet.
If you won't mind to share some of your country/are specific database files, I think I can arrange hosting on the modRana project website for them. Users would then just download a corresponding database file and run the import script.

Of course a proper, more automated (building, distribution & import) solution tile package handling should be implemented eventually.

BTW, just got a and email from Beermad, the import script is back on-line !

Originally Posted by jafd View Post
An idea worth considering: an empty tile takes 103 bytes as a file + storage overhead of a row in SQLite. At high zoom levels, OSM has lots of those. Maybe it's worth to have one more column in the lookup table to indicate an empty tile and thus process it more quickly?
Are they all really the same & how can they be reliably identified (eq, when downloading tiles) ? What about ocean tiles ?

So something like this ?

Code:
table tiles (z integer, x integer, y integer, store_filename string, extension varchar(10), unix_epoch_timestamp integer, empty integer, primary key (z, x, y, extension))
1 = empty
0 = nonempty

And possibly other values (like for ocean or other solid-color tiles). But that might be taking it too far & unnecessary complicating it (also something like that should be probably in the store database, not in the lookup one).

EDIT: On the other hand, solid color PNG tiles should be really small, so probably not worth the bother & database handling complications.
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modRana: a flexible GPS navigation system
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Last edited by MartinK; 2012-03-14 at 16:03.
 

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