Wahts wrong with this situation?
finish line
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Goes back to what I've always said - a line is determined by TWO points.
This could be solved in two ways:
1. Have the runners make a 90 degree turn when entering the finish straight, thus the finish line would be an extension of the back wall of the YMCA;
2. If that's not possible, indicate that the finish line is perpendicular to the direction of the runners. I think this would require a second distance, from the turn off the road into the field, to make it more accurate.
This could be solved in two ways:
1. Have the runners make a 90 degree turn when entering the finish straight, thus the finish line would be an extension of the back wall of the YMCA;
2. If that's not possible, indicate that the finish line is perpendicular to the direction of the runners. I think this would require a second distance, from the turn off the road into the field, to make it more accurate.
If the finish is a single point in a large undefined surface like a field or a parking lot, it really needs to be defined by measurements from a minimum of two separate landmarks. There shouldn't be any confusion about where it is or how it was measured.
Jay, that's true! However, how is the entire line drawn for the finish. Is it Parallel to the street or is it an an angle? One single point will not work.
For all practical purposes it will, depending, of course, on the length of the last straight section before the finish.
The finish line is perpendicular to the last straight section of the course. If it's on a street it's perpendicular to the curb or edge of the pavement. If it's on a curve it's the radius of the curve extended through the point.
I've now measured over four hundred courses. If I've EVER used more than a point to document the finish I don't remember doing so unless it was the finish line of a track.
If you want a nice hypothetical question, what is the separation of an out-loop-back course that starts and finishes at the same line, is a straight road until the first turn and from the last turn home, and the first and last turn are in the same direction (meaning the only street the course travels twice is that first/last segment)?
The finish line is perpendicular to the last straight section of the course. If it's on a street it's perpendicular to the curb or edge of the pavement. If it's on a curve it's the radius of the curve extended through the point.
I've now measured over four hundred courses. If I've EVER used more than a point to document the finish I don't remember doing so unless it was the finish line of a track.
If you want a nice hypothetical question, what is the separation of an out-loop-back course that starts and finishes at the same line, is a straight road until the first turn and from the last turn home, and the first and last turn are in the same direction (meaning the only street the course travels twice is that first/last segment)?
Separation - on a course that starts and finishes at the same point? I am confused.
quote:Originally posted by Gene Newman:
Jay, that's true! However, how is the entire line drawn for the finish. Is it Parallel to the street or is it an an angle? One single point will not work.
Seems to me that Jay has the solution. If a line is drawn from the last turn of the course - in this case the turn tangent from Jones Avenue - to the finish point, the finish line is then defined as a line that intersects the finish point and which is 90 degrees to the aforementioned line from the turn. By geometry, no point on this line will be closer to the turn than the finish point. How wide the line needs to be is then determined by the timing system and the estimated finish density. Right?
That's my take on things.
On the example I gave, in theory the start is on one side of the street and the finish is on the other. They're on the same line- just the width of the street apart. I would normally use just one nail to describe both start and finish- but, technically, there is a bit of separation here.
On the example I gave, in theory the start is on one side of the street and the finish is on the other. They're on the same line- just the width of the street apart. I would normally use just one nail to describe both start and finish- but, technically, there is a bit of separation here.
Lyman, is this line drawn to the East, West or both?
How about a certified point at the turn (similar to how we document a ta)and finish each triangulated to at elast two points. That would get the job done.
Per Jay's post, the finish line is typically defined as a single point with the assumption that the finish line is perpendicular to the shortest distance of the direction of the runners. If the finish line is perpendicular then in my opinion it does not need any more definition other than stating so. Running to the west or the east of the point will result in a longer distance traveled. What Gene's problem merely needs is a better description (both written and in the sketch) of where the intended finish line is. From the sketch, if I was the timer setting up the finish line, I would assume that the finish line was east of the given point. Whether it was in line with the north wall of the YMCA building or perpendicular to the direction of finishing runners would not matter.
quote:Originally posted by Gene Newman:
Lyman, is this line drawn to the East, West or both?
Gene, it seems to me that from a measurement perspective, it doesn't matter since it does not shorten the course distance nor would any of these choices lengthen it materially. Lacking additional race logistical criteria, my intuition is to draw the line an equal distance on both sides of the point.
quote:Originally posted by Lyman Jordan:
draw the line an equal distance on both sides of the point.
...providing that the finish line is perpendicular to the direction of the finishing runners...
right, Matthew:
"...the finish line is then defined as a line that intersects the finish point and which is 90 degrees to the aforementioned line from the turn."
"...the finish line is then defined as a line that intersects the finish point and which is 90 degrees to the aforementioned line from the turn."
quote:Originally posted by Gene Newman:quote:Originally posted by Gene Newman:
I now got a second problem S/F line. I gave a solution. Any comments appreciated.
Here is the link!
https://www.icloud.com/journal...08-A5FD-39B367366B99
Although not specifically stated, in lawyer terms, as a requirement, all the maps in the Measurement Procedures Manual show a line (not a point) for the start and finish lines. This simple feature seems to eliminate all doubt. Why would the certifier not ask for a line to be added to the map, or add lines if agreed by the measurer?
Good point. Thanks!