1. Cochrane Day

    Cochrane Day New Member


    Source: https://www.youtube.com/watch?v=FzT9uLKPpvw
    There's [someone] on Youtube who is using your calculator and offsetting everything by 5000 feet as that is his "base line height" in Colorado.

    I've corrected his maths and used the formula from your earlier spreadsheet version to explain why he is wrong.

    But next time you are editing the curve page then changing "Viewer height in Feet" to "Viewer height above sea level in Feet" my dissuade further jokers.

    Great site and work by the way.
     
    Last edited by a moderator: Nov 29, 2017
  2. Mick West

    Mick West Administrator Staff Member

    He's not wrong. If there's nothing below 5,000 feet between the viewer and the target, then you can effectively say 5,000 feet is sea level. The height above sea level is only relevant if you can see the ocean horizon.
     
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  3. Mick West

    Mick West Administrator Staff Member

    From that video, here's a fit to a "flat earth" view:
    24129992_10155413453154514_4052387869398221937_n.

    A new technique is to use the snow features in the above image and the red line to adjust a plane to intersect the mountain at the same position. Then you can find the actual amount of "hidden" for this situation.
    24176757_10155413501904514_6329589502639824945_n.

    And the top of the mountain is just below eye level.
    20171130-094718-8gysu.
    hat's because there's a drop of 9130 feet, plus the view height of 5177 feet = 14,307, and the peak is 14,114 feet.
     
    Last edited: Nov 30, 2017
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  4. Rory

    Rory Senior Member

    It's interesting that he does some half-decent background math and then when it comes to comparing his image he ignores any attempt at methodology and merely concludes "there's no way you should be able to see that."

    Strange also that he doesn't notice the massive difference between reality and the diagram he's comparing his image to - particularly with regard to the shape of the summit:

    pp3.JPG

    My first question if I were him might be: "is this diagram an actual drawing of Pikes Peak, or is it merely illustrative?"

    Comparing it with photos of Pikes Peak from the south clearly indicates the latter.

    I had a look on peakfinder and by entering a viewer closer to Pikes Peak, but along the same line of sight, we get a good representation of his image:

    pkfndr.

    Sentinel Point, therefore, is some distance outside his image, while the peak of Satchett Mountain, at 12,590 feet, is just hidden by the ridge.

    I also looked at images from Woodland Park, which is on the same line of sight but only around 10 miles from Pikes Peak. It's pretty easy to match up the various peaks and troughs:

    woodlandpark.

    The peaks would be pretty easy to identify and verify by taking compass readings. I'm sure if the video maker had done this he could have worked out that he wasn't actually seeing Sentinel Point, nevermind the 5000 feet below this.

    I have slightly different figures for his position, with a GPS of 40.526265, -105.115231, elevation of 5162 feet (not including tripod), and distance to Pikes Peak of 116.5 miles. Shouldn't think that would change much though.

    Mick makes a great point about the summit of Pikes Peak being below eye level too: if the video maker goes back he could measure it with a theodolite: on a flat earth the peak would be about 0.8° above eye level, whereas in reality it's about 0.1° below. That should be pretty easy to discern. And a much better way to figure out the shape of the earth than trying to use 'hidden amount', given that his shot doesn't actually have a horizon in it.
     
    Last edited: Dec 2, 2017
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  5. Rory

    Rory Senior Member

    A note on using peakfinder.org

    Peakfinder is a very useful tool when it comes to identifying mountain summits. But one thing I've noticed is that the posted elevations are often quite different to USGS and NAVD88 figures, which I believe are the most reliable.

    The reason for this is that peakfinder uses openstreetmap.org for its data, which is a system of mapping "built by a community of mappers that contribute and maintain data about roads, trails, cafés, railway stations, and much more, all over the world."

    In other words, it's a bit like wikipedia, and therefore editable by anyone, which makes it more prone to error.

    In a nutshell: peakfinder for indentifying mountains, but NAVD88 for elevations.