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20936Re: [aprsisce] Maps space vs sector size idea

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  • Lynn W Deffenbaugh (Mr)
    Nov 21, 2012
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      One of the "compression" ideas I'm toying with is actually detecting any single-color tile and flagging it as special in whatever kind of container I end up implementing.  I've already done some work in this area, but that was a while ago.

      Another impetus for doing some sort of tile containerization (besides the space savings) is the ability to store meta-data about the tiles like access frequency, last access time, last fetch time and so forth.  Currently I only have access to the file system timestamps on which I cannot rely having separate timestamps for accessed vs created.  I'm working towards a smarter purger that keeps the recently accessed tiles as well as a way of (slowly) checking the /status (for those tile sets that support it) for cached tiles to refresh the cache for those that you're actually referencing.

      Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

      On 11/21/2012 11:50 AM, Patrick Wood wrote:
      I have a handful of other tile sets, but this one looks to be the culprit

      Original->./OSMTiles/
      1104690/3.41GB/6.20GB(*4KB) 28.86GB Free

      Looking at it I would bet that a lot of the problem is water tiles.. I think I will have to script a way for my external tile scripts to detect a solid blue tile and remove them.

      p

      On Wed, Nov 21, 2012 at 11:28 AM, Lynn W Deffenbaugh (Mr) <kj4erj@...> wrote:


      What is the cluster size on your 119G drive?  That'd be the number in () if you double-click an empty space on your map in the space reports for your various tile sets like:

      <Lots of other stuff clipped out>

      Original->D:/OSMTiles/OSMTiles/
      894/7.08MB/9.11MB(*4KB) 253.01GB Free

      MQ Aerial->D:/OSMTiles/MQAerial/
      279/2.84MB/3.41MB(*4KB) 253.01GB Free

      MyOSM->D:/OSMTiles/MyOSM/
      2473/23.96MB/29.59MB(*4KB) 253.01GB Free

      Those are on a 500GB drive, but it's formatted NTFS with a 4KB cluster size, so there's not much waste.  Certainly nothing approaching 50%!


      Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

      On 11/21/2012 11:22 AM, Patrick Wood wrote:
      Steve you just have a small map set...and perhaps smaller disks..  on my 119 gig drive I'm closer to 40-50% of wasted space.  Don't mind losing 3 gig of space to go portable with any of my map sets, but would be nice to put it to other uses.

      p

      On Wed, Nov 21, 2012 at 11:05 AM, Steve Daniels <steve@...> wrote:


      I just did a quick test by zipping my OSM directory, you don’t save any space from a file size point of view, but with 22MB of files, size on disk dropped from 27MB to 22MB, so it is worth considering some sort of “packing” for a 20% reduction in disk space used. (I rounded the figures)

       

      Steve Daniels

      Amateur Radio Callsign G6UIM

      Torbay Freecycle  Owner

      http://http://uk.groups.yahoo.com/group/torbay_freecycle

      APRSISCE/32 Beta tester and WIKI editor http://aprsisce.wikidot.com

       


      From: aprsisce@yahoogroups.com [mailto:aprsisce@yahoogroups.com] On Behalf Of Lynn W Deffenbaugh (Mr)
      Sent: 21 November 2012 05:17
      To: aprsisce@yahoogroups.com
      Subject: Re: [aprsisce] Maps space vs sector size idea

       

       

      Not that I know of, but if someone wants to take the time to track down
      such a "container file" approach for Windows Mobile (and optionally
      WinCE, but that's much more unlikely), I'd be glad to learn of it.

      Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

      On 11/21/2012 12:10 AM, Greg D wrote:
      > Hi Lynn,
      >
      > I wonder... I've been using an aging yet trusty HP 100LX Palmtop for
      > many years (since 1995, actually), and one of the techniques people use
      > to optimize space is to use a compressed drive. The technology of the
      > day was Stacker, then came DoubleSpace with Windows. The main purpose
      > was to get more space out of the limited drives then available (often up
      > to 2x), but a side effect was that the apparent sector size of the
      > compressed drive was fairly small.
      >
      > Are there any equivalent utilities for WinCE (a verb) that would create
      > a new folder with files in it when you CD to it, but look like one big
      > file from the outside? That way you wouldn't have to use or invent your
      > own database, and you'd have full portability of the contents. Just
      > point to it and go.
      >
      > Just a thought,
      >
      > Greg KO6TH
      >
      >
      >
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