[OSM-dev] How is the tile-index implemented/used?
osmmaillst at danielgilbert.de
Thu May 14 13:54:09 BST 2009
Hi Tom, Hi Frederik,
> Basically you can ignore the complicated stuff on that wiki page - the
> only part we did is the first bit of dividing each line of lat/lon
> into 65536 equal parts to get to 16 bit numbers which are then
> interleaved to get a single 32 bit tile ID value.
Thanks for pointing this out. ;)
I plan to do the following:
From http://download.geofabrik.de/osm/ you can download "pre-cut"
OSM-files for a single country (at least this applies to europe). Now I
wrote a SAX-parser for the OSM-data, which works quite well (it's
written in Delphi, maybe one day I'll port this to Delphi Prism). So
it's native Win32-code. The parser writes the data into an embedded
To speed up rendering and displaying, I thought about splitting the
world into tiles, like all the well-known web-renderer do. And now it
would be interesting to know, how the renderer determines wether a node
or a way belongs into a tile or not.
I guess the Lat/Lon conversion you described above allows me to
determine all the nodes which are in a special area and then create a
tile from it. I checked out the svn and came across the quad_tiles.h.
Seems to me as if it contains the functions I would need to do the
conversion, doesn't it?
My goal is an easy-to-use Windows application, which requires no
additional knowledge. Simply download the country you want, import it by
clicking a button and be happy. Then you can search for streets, towns
or POI in general. Might maybe help to spread the word of OSM into the
P.S.: Hopefully this message gets posted to the mailinglist...
Thunderbird is somehow "strange" in terms of mailinglist-usage, which
unfortunately multiplies with the user's ignorance..
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