google-code-export / gccv2

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ZIP-Support for OSM tiles #13

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago
Hi,
is it possible to add a support to gcc for a set of OpenStreetMaps tiles
compressed in a single file, like a zip file? This would save much of disk
space and upload time to the phone or storage card. Especially when you use
maps with a very high zoom range consisting of a dozen of tiles (about
200000 or more). Every single tile is using more disk space on the storage
card then the tile file itself because of the allocation of the clusters on
the storage card. Copying many single file on a storage card will leave
many half used clusters, that means much of unusable disk space. I.e. a set
of 300000 tile have a file size of 1.6 GB. But on the storage card the
files are using more then 2.1 GB of disk space. Compressing them to a singe
file with the size of 1.4 GB it will also use nearly 1.4 GB on the storage
card.

Thank you,
MaMaHa

Original issue reported on code.google.com by muel...@googlemail.com on 22 Apr 2009 at 10:30

GoogleCodeExporter commented 9 years ago
Totaly agree. An other program I'm using is cachebox for geocaching, but is 
missing the 
very nice tracking op gps cycle computer. With the cachebox program 
(http://www.getcachebox.net/en/download.html) mapbox is delivered, a very 
simple 
program for downloading tiles and packing them in a .pack file. Maybe gps cycle 
computer can use the same mapbox program.

Original comment by mjur...@gmail.com on 12 Aug 2009 at 8:49

GoogleCodeExporter commented 9 years ago
Hi,
I think this should rather be categorized as enhancement, not a defect. Anyways 
it
would be really cool thing to have to reduce the files slack. But I guess it 
would
rather complicate the original idea of the ability to download the tiles that 
are
missing (would be kind of costly to zip them into the archive). It would be 
necessary
to support multiple sources (dir and zip) to load from.
Although I wouldn't require the ability to download the missing in such case.

In the meantime, I've solved my problem with files slack by reducing my storage
card's FAT32 cluster size down to 8192B. This reduced the files slack of my OSM 
tiles
(4,46GiB, zooms 0-15) down to 15% (now they use up only 5,28GiB). Windows 
defaultly
formatted my card's with cluster size 32768B which produced a lot of slack. 

http://www.pcguide.com/ref/hdd/file/partFAT32-c.html
I didn't want to set the cluster size too low as it might increase the FAT too 
much.
With this cluster size the FAT of my 16GB storage card is approximately 8MiB. 
I've
been using it like this for about a month. So far I haven't experienced any
performance drawbacks.

Original comment by jakub.sa...@gmail.com on 7 Jun 2010 at 4:44

GoogleCodeExporter commented 9 years ago
I successfully used a trick with reformatting SD card with lesser custer size 
to reduce storage space waste. 

However, a feature of using some sort of single-file DB would still be nice. 
For example, a sattelite view of my town and area at zoom level 17 would take 
800 Mb in a single ECW file. The same data being ported to OSM storage would 
take 15 Gb, not including additional cluster slack.

Original comment by randomcl...@gmail.com on 26 Nov 2013 at 2:04