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Thread: Time slider - another query

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    Default Time slider - another query

    These two screenshots show what I see as I drag the End slider to the right:






    Probably obvious, but I don't understand what that second time is that appears after a while? What is it and why does it appear please?

    --
    Terry, East Grinstead, UK
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    Last edited by terrypin; 02-07-2011 at 10:07 AM.

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    Moderator Emeritus Appletom's Avatar
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    Can you attach the kmz file so we can play with it to try and figure it out?

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    Quote Originally Posted by Appletom View Post
    Can you attach the kmz file so we can play with it to try and figure it out?
    OK, thanks Appletom, duly attached.

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    Terry, East Grinstead, UK
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    Moderator Emeritus Appletom's Avatar
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    You have the time slider broken into two pieces. The second time is the time of the trailing edge.

    It's tough to explain. Play with the slider by setting the leading and trailing edges to be about 45 minutes apart. Now zoom way out—about 38,000 feet so you can see your entire trail, and move the big part of the slider and watch the "snake" on your path.

    Here's a screenshot. The dark red is the "snake" representing your travel between 12:45 and 1:30. The light red represents your entire walk. (18 kilometers in 6 hours, I'm impressed. Looks like it was a beautiful walk.)



    If you move the big part of the slider, the snake will slither with the head and the tail moving and the body always staying 45 minutes long. If you move the little side of the broken slider, the snake will get longer and shorter with the head staying in the same spot.

    Make sense? If not, let me know and I'll do a video for you this weekend.

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    Thanks Appletom, much appreciate your taking the time and trouble.

    But I still don't see why that second time suddenly appears. Why doesn't it display from the start?

    Whether you run it automatically or drag manually, it only appears when the front slider reaches about 7:23, and then shows 1:29. The back marker stays fixed at the left throughout. The diffrerence between those values (5:54) looks very close to the walk's duration. So I've almost grasped it, but not quite!

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    Terry, East Grinstead, UK

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    Moderator Emeritus Appletom's Avatar
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    That's easy. The trailing time only shows up if there is enough room for it to be visible.

    When I changed my slider's time zone to be UTC (same as Isle of Wight) then the trailing edge is not visible at 7:06, but it becomes visible at 7:07. It doesn't matter how close or far the trailing slider is.

    If I change the time zone to Mountain Standard, then the trailing edge won't show up until 12:11 due to the extra digit in the time display.

    Edit - I also noticed that the trailing edge disappearance act happens on both sides of the time slider. Move the big piece to the far right and move the little piece back and forth. You'll notice the trailing time can only go up to 8:59.
    Last edited by Appletom; 02-08-2011 at 01:14 PM.

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    Quote Originally Posted by Appletom View Post
    That's easy. The trailing time only shows up if there is enough room for it to be visible.
    Ah, yes, many thanks!

    When I changed my slider's time zone to be UTC (same as Isle of Wight) then the trailing edge is not visible at 7:06, but it becomes visible at 7:07. It doesn't matter how close or far the trailing slider is.
    This must depend on our individual PC specs or settings, because my first appearance of the trailing time is when the leading time is 7:23.
    GE-TS-TrailTimetAppears.jpg

    But what does the trailing time of 1:29 am mean? The leading time shows where I am now (just about to walk around Bembridge Harbour at 7:23, 2:18 since I started. But what is 1:29? That's hours before the 'base' time of 5:00. (BTW, all these times somehow got reduced by 5 hours in the original GPX. I actually started at 5 minutes past 10 am.)

    If I change the time zone to Mountain Standard, then the trailing edge won't show up until 12:11 due to the extra digit in the time display.

    Edit - I also noticed that the trailing edge disappearance act happens on both sides of the time slider. Move the big piece to the far right and move the little piece back and forth. You'll notice the trailing time can only go up to 8:59.
    Here again, my display is different: 8:37 not 8:59

    GE-TS-3.jpg

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    Terry, East Grinstead, UK

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    Moderator Emeritus Appletom's Avatar
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    Quote Originally Posted by terrypin View Post
    Ah, yes, many thanks!
    You are very welcome. For some reason that time slider just completely stumps you and for some even weirder reason I can intuitively figure out its idiosyncrasies. (Though your 1:29 query had me stumped all last night. But it took just one look this morning before the light bulb went off.)

    This must depend on our individual PC specs or settings, because my first appearance of the trailing time is when the leading time is 7:23.
    Yes, we have different displays. Look closely at the graphics on our timesliders and you can see how mine are "blockier" and larger than yours. Do you use a Mac? I've got a PC with Windows 7.

    But what does the trailing time of 1:29 am mean?
    It means you had the slider points were 5:54 apart when you started moving the big piece to the left.

    Try this and it will make sense - set the leading slider to 10:30 am, and the trailing slider to 5:30 am. Now as you move the big slider, the trailing time will always show 5 hours before the big slider time.

    In other words, the clock representing the small slider doesn't know the slider has stopped and it just keeps going backwards. You have discovered an honest to goodness bug in Google Earth.

    The leading time shows where I am now (just about to walk around Bembridge Harbour at 7:23, 2:18 since I started. But what is 1:29? That's hours before the 'base' time of 5:00.
    5:54 before the current time. No matter where you move the big slider the two times would always vary by 5:54.

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    Quote Originally Posted by Appletom View Post
    Do you use a Mac? I've got a PC with Windows 7.
    This is a PC, but with a 24" screen set to 1920 x 1200.

    It means you had the slider points were 5:54 apart when you started moving the big piece to the left.
    Of course! Thank you - obvious now I know ;-)

    Try this and it will make sense - set the leading slider to 10:30 am, and the trailing slider to 5:30 am. Now as you move the big slider, the trailing time will always show 5 hours before the big slider time.

    In other words, the clock representing the small slider doesn't know the slider has stopped and it just keeps going backwards. You have discovered an honest to goodness bug in Google Earth.
    Sorry, but that opens up another bunch of stuff I don't follow. You're right, I have a mental block about the whole thing! So, while you're on a roll:
    1. Why don't those changes survive: opening/closing the settings? playing with the sliders?
    2. How do you increase the end slider time? Presumably it's because of the range, so...
    3. Where does that range of 5 AM - 10 AM come from?
    4. How do you change it?
    And, most important of all
    5. How are you meant to use this darn thing in practice? Apart from setting it up to 'play' the walk from start to finish, with the path appearing until complete, I don't grasp its purpose for GPS tracks like this.

    I suspect my confusion stems from being unable to distinguish the respective roles of GE, versus the KML code in the file itself. Stand well clear - a large penny must soon drop!

    --
    Terry, East Grinstead, UK

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    Moderator Emeritus Appletom's Avatar
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    1. Why don't those changes survive: opening/closing the settings? playing with the sliders?

    It will if you ask it to. Look at this file of your walk I attached. 20100531-Walk3.kmz

    How? you ask? Simple:

    1. Set the sliders the way you want them.
    2. In your My Places, click the little plus button to "open" the filename and then right-click on the "sub" file.
    3. Select Properties.
    4. Click on the View tab.
    5. In the Date/Time drop down menu select Time Span.
    6. Then click the Snapshot Current View button.
    7. Now save the file and the sliders are where you left them.

    2. How do you increase the end slider time? Presumably it's because of the range, so...

    By taking longer walks :-). Remember, the end slider is the "primary" slider. When you move the end one, the trailing slider moves in lock-step. But if you move the trailing slider the leading one stays put. In other words, the big slider can push and pull the little slider around, but the little slider can't push or pull the big slider. The big slider can't move independently of the little slider.

    3. Where does that range of 5 AM - 10 AM come from?

    I just picked two times that were exactly x hours apart making it easy to see the difference since the minutes displayed always matched. The value of "x" just happened to be 5. I could have just as easily chosen 5 AM to 9 AM.

    4. How do you change it?

    I lost you here—change what? Change the 5:00 and 10:00? By moving the sliders.

    And, most important of all
    5. How are you meant to use this darn thing in practice?


    I have absolutely no idea, I didn't even know the slider would break apart until you (I think it was you, it was a few months back) asked in another thread.

    Apart from setting it up to 'play' the walk from start to finish, with the path appearing until complete, I don't grasp its purpose for GPS tracks like this.

    Me either.

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    Thanks for sticking with me on this!

    Quote Originally Posted by Appletom View Post
    1. Why don't those changes survive: opening/closing the settings? playing with the sliders?
    It will if you ask it to. Look at this file of your walk I attached. 20100531-Walk3.kmz

    How? you ask? Simple:

    Well, maybe, but not that intuitive!

    1. Set the sliders the way you want them.
    2. In your My Places, click the little plus button to "open" the filename and then right-click on the "sub" file.
    3. Select Properties.
    4. Click on the View tab.
    5. In the Date/Time drop down menu select Time Span.
    6. Then click the Snapshot Current View button.
    7. Now save the file and the sliders are where you left them.
    Thanks, understood. My hangup was that having selected Time stamp from the drop-down list, it reverts to None. So I'd assumed that was a bug (it probably is) and didn't proceed any further.
    2. How do you increase the end slider time? Presumably it's because of the range, so...
    By taking longer walks :-). Remember, the end slider is the "primary" slider. When you move the end one, the trailing slider moves in lock-step. But if you move the trailing slider the leading one stays put. In other words, the big slider can push and pull the little slider around, but the little slider can't push or pull the big slider. The big slider can't move independently of the little slider.


    OK, got it. The two times are inherent in the KML (originally GPX) file.


    3. Where does that range of 5 AM - 10 AM come from?
    I just picked two times that were exactly x hours apart making it easy to see the difference since the minutes displayed always matched. The value of "x" just happened to be 5. I could have just as easily chosen 5 AM to 9 AM.


    No, what I meant was where do those two times come from in the first place. But I've now worked it out. They are calculated by GE, and are clearly intended to be the nearest exact hour at either end of the start and end times respectively. But unfortunately GE gets the latter one wrong, rounding down instead of up! That's what was baffling me: how could a walk finishing at 10:59 be inside a range finishing at 10?!

    I made another KML by stripping out entries from the end, so that the walk finished at 9:26 AM. GE now wrongly shows the max end of the range as 9 AM instead of 10 AM.

    GE-TS-4.jpg


    4. How do you change it?
    I lost you here—change what? Change the 5:00 and 10:00? By moving the sliders.


    See above.
    And, most important of all
    5. How are you meant to use this darn thing in practice?
    I have absolutely no idea, I didn't even know the slider would break apart until you (I think it was you, it was a few months back) asked in another thread.
    Apart from setting it up to 'play' the walk from start to finish, with the path appearing until complete, I don't grasp its purpose for GPS tracks like this.
    Me either.
    For GPS files I think that's about it! So it probably comes into its own when looking at
    'historical' data in multiple files. There's a fair bit of documentation around, but I haven't got into that stuff yet.

    --
    Terry, East Grinstead, UK

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    Moderator Emeritus Appletom's Avatar
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    Thanks for sticking with me on this!
    It's been a fun trip.

    But unfortunately GE gets the latter one wrong, rounding down instead of up! That's what was baffling me: how could a walk finishing at 10:59 be inside a range finishing at 10?!
    Now I understand the question. And I think you have found a second time slider bug!

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    Now here's an interesting thing. When I download your KMZ and open it in GE, it allows me to manipulate the time slider in any way I desire:

    Time Slider.jpg

    I wonder if this difference in behavior is defined by gpx vs. kmz. Have you tried opening the kmz you provided us in GE? I got results by right-clicking on the route file itself (20100531-HF-Day3).
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    Thanks Terry. Yep, I've been using the same KMZ file as you, ever since I sent it to Appletom, so that I was in sync during our subsequent discussions. Have you been following along?

    I'm not sure I know what you mean by 'manipulate'. Drag the two sliders? I can do that.

    Or manually edit the values using the Tools icon? I can do that (within the obvious limits of the original start and end times).

    Or use Properties > View > Date/Time? I can do that, as described up-thread. But do you agree with the bug I identified in GE's calculation of the range?

    Or is there something I've misssed?

    --
    Terry, East Grinstead, UK
    Last edited by terrypin; 02-13-2011 at 06:55 PM.

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