[OSM-talk] Download all OSM GPS traces

Ruogu Ding ruogu.ding at kaust.edu.sa
Mon Apr 9 20:13:46 BST 2012


Hi,

I find a "planet.gpx" is being offered but with only GPS points. I
understand that this is helpful, and appreciate the efforts in
generating this file. However, many people (like me) need GPS traces
instead of individual points, and I personally prefer to see the
associated descriptions too. Is it possible to compress all uploaded
.gpx files and offer this large file for download? Identifiable traces
are sufficient, if privacy is a problem.

Alternatively, is it possible to offer the planet.gpx like this:

450000000,450000000
450000001,450000000
450000002,450000000
910000000,1810000000
330000000,660000000
330000000,660000001
330000000,660000002

In this way, we know that there are two traces, one of which is near
45N,45E while the other is near 33N,66E. Note that
"910000000,1810000000" is not realizable and is used as a seperator.

To save space, I also suggest to use two 4-byte integers to store the
coordinate pair. The maximum value 1810000000 is within the limit of a
signed 4-byte integer, which is 2147483647. According to the stats,
there are 2811827999 uploaded GPS points, and each point takes only 8
bytes in this way - that is 22GB binary file instead of 55GB text file
now.

Thanks,

Ruogu Ding (丁若谷)
King Abdullah Univ. of Sci. & Tech.
+966-562609061
ruogu.ding at kaust.edu.sa



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