Page 2 of 2 FirstFirst 12
Results 11 to 16 of 16

Thread: New mp3car passive maps server

  1. #11
    SuperMod - OBDII GPS Logger forum
    Auto Apps:loading...

    Join Date
    Mar 2009
    Location
    Los Angeles
    Posts
    924
    Before it gets too late to change this, are we absolutely sure that DDMMYYYY is the best way to go? Among other things, DDMM is an unusual or confusing order for many people outside of europe. A useful short discussion of ISO8601 is here. The most important reasons to use ISO date format in my experience are twofold:
    1) Unambiguous. I deal with people from the UK and the US on a daily basis, and an unambiguous date format is the difference between effing nightmare and ... not effing nightmare
    2) Sortable. Working through a huge directory listing to find "the nearest trace to a specific date" is a nightmare

    Specifying time - what use will that be, other than to separate tracks from the same day? If the time is used to mean anything, then should it be converted to UTC? If not, then a TZ suffix is important.

    More on the list of "nightmare things I have to deal with on a regular basis"

    Gary

    PS Apologies if this is in the realm of the bikeshed, but date formats are a particular bugbear to me.
    OBDGPSLogger, for logging OBDII and/or GPS data
    OBDSim, an OBDII/ELM327 software simulator
    mp3car forums: obdgpslogger, obdsim

  2. #12
    is back. FKA Robert Wray
    Auto Apps:loading...
    Fiberoptic's Avatar
    Join Date
    Jul 1978
    Location
    Baltimore, MD
    Posts
    1,419
    Blog Entries
    143
    Quote Originally Posted by chunkyks View Post
    Before it gets too late to change this, are we absolutely sure that DDMMYYYY is the best way to go? Among other things, DDMM is an unusual or confusing order for many people outside of europe. A useful short discussion of ISO8601 is here. The most important reasons to use ISO date format in my experience are twofold:
    1) Unambiguous. I deal with people from the UK and the US on a daily basis, and an unambiguous date format is the difference between effing nightmare and ... not effing nightmare
    2) Sortable. Working through a huge directory listing to find "the nearest trace to a specific date" is a nightmare

    Specifying time - what use will that be, other than to separate tracks from the same day? If the time is used to mean anything, then should it be converted to UTC? If not, then a TZ suffix is important.

    More on the list of "nightmare things I have to deal with on a regular basis"

    Gary

    PS Apologies if this is in the realm of the bikeshed, but date formats are a particular bugbear to me.
    The theory behind the seconds was to create multiple file names if more than one file was created in the same minute for some reason.

    I like the idea of international standards, and good point about converting to UTC.

    Anyone else have an opinion on this?

  3. #13
    is back. FKA Robert Wray
    Auto Apps:loading...
    Fiberoptic's Avatar
    Join Date
    Jul 1978
    Location
    Baltimore, MD
    Posts
    1,419
    Blog Entries
    143
    The gist of that iso link is here:

    Basically to comply with the 'full' ISO format you need to:
    - Use 4-digit years when storing or printing dates.
    - Use the order Year-Month-Day for the date, i.e. biggest first.
    - Use leading zeroes on the digits 00 - 09 for the month and day numbers.
    - Always put the Date BEFORE the Time.
    - Use the order hours:minutes:seconds for times.
    - Use the 24-hour format for times (not the 12-hour am/pm).
    - Use a leading zero on hour, minute and second for digits 00 - 09 inclusive.
    - Use UT time scale for dates and times if transferring data internationally.
    - When printing dates and times use the '-' and ':' separators.
    e.g. 1996-12-31 23:59:59 is the last second of last year.
    - When storing dates you can strip off the separators and store as a 32-bit
    number, an ASCII string, packed BCD or whatever you like. Sort algorithms
    are much easier with this YMD format.
    - Times can be treated the same way (sorted or stored), as in the discussion
    for dates.

  4. #14
    Variable Bitrate
    Auto Apps:loading...
    thekl0wn's Avatar
    Join Date
    Apr 2005
    Location
    PoCo, Indiana
    Posts
    284
    Correct me if I'm wrong, but didn't I read in the NMEA information that the timestamps used in sentencing is UTC? This is an important bit of info for parsing the files.

    And I'm all-for the YYYYMMDD and HHMMSS formats! As for naming conventions, is the filename for first recorded second?
    Play with it, 'til it's broke.

  5. #15
    SuperMod - OBDII GPS Logger forum
    Auto Apps:loading...

    Join Date
    Mar 2009
    Location
    Los Angeles
    Posts
    924
    Basically to comply with the 'full' ISO format you need to:
    - Use 4-digit years when storing or printing dates.
    - Use the order Year-Month-Day for the date, i.e. biggest first.
    - Use leading zeroes on the digits 00 - 09 for the month and day numbers.
    - Always put the Date BEFORE the Time.
    - Use the order hours:minutes:seconds for times.
    - Use the 24-hour format for times (not the 12-hour am/pm).
    - Use a leading zero on hour, minute and second for digits 00 - 09 inclusive.
    - Use UT time scale for dates and times if transferring data internationally.
    - When printing dates and times use the '-' and ':' separators.
    e.g. 1996-12-31 23:59:59 is the last second of last year.
    - When storing dates you can strip off the separators and store as a 32-bit
    number, an ASCII string, packed BCD or whatever you like. Sort algorithms
    are much easier with this YMD format.
    - Times can be treated the same way (sorted or stored), as in the discussion
    for dates.
    Sounds right. It's worth noting that : in filenames is bad karma [no matter what the standards may say], so I always store the time packed without separators.

    A simpler rule to remember ordering is "it's big endian" - store units biggest-first. Eg, years are bigger than months, and days are bigger than hours.

    Yes, grabbing the timestamp exactly as the NMEA sentence mentions it is UTC, but a lot of userland programs will be converting to local time, so beware.

    Gary (-;
    OBDGPSLogger, for logging OBDII and/or GPS data
    OBDSim, an OBDII/ELM327 software simulator
    mp3car forums: obdgpslogger, obdsim

  6. #16
    Admin. Linux loser.
    Auto Apps:loading...
    Bugbyte's Avatar
    Join Date
    Sep 2004
    Location
    Corning, NY
    Posts
    7,359
    Blog Entries
    2
    +1 for UTC. Let the user convert it. Settling on a single timestamp will make sorting and ordering it much easier. Agree also with the ISO format.
    Quote Originally Posted by ghettocruzer View Post
    I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
    Want to:
    -Find out about the new iBug iPad install?
    -Find out about carPC's in just 5 minutes? View the Car PC 101 video

Page 2 of 2 FirstFirst 12

Similar Threads

  1. FAQ: OpenStreetMap - free maps and routing
    By RussNelson in forum The FAQ Emporium
    Replies: 0
    Last Post: 06-05-2009, 10:21 PM
  2. RR's Commitment to the Mp3Car forums
    By guino in forum Road Runner
    Replies: 0
    Last Post: 06-05-2009, 04:58 PM
  3. StreetDeck Status
    By Fiberoptic in forum StreetDeck
    Replies: 173
    Last Post: 07-18-2008, 06:36 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •