Replies

1. 
   Guest_ | Apr 05, 2000 10:59pm | #1

   *

   jim,

   < Obsolete Link > Here's the answer.

   View Image

   © 1999-2000

   "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."

   Aristotle

1. 
   Guest_ | Apr 05, 2000 11:01pm | #2

   *jim... i thot about it, and i considered it,, and i even bit my tongue... but in my humble opinion.....i .. think ..yur wrong....i think the tool is a variation on the and if so, it does draw a true ellipsebut i cud be wrong...maybe the tool ryanc was talking abot was not a variation of the card method..b but hey, whadda i know

1. 
   Guest_ | Apr 06, 2000 12:40am | #3

   *I'm not sure that everyone understood how this tool worked. So, for your viewing pleasure, I made a stupid kindergarten animation of this thing. Maybe this will help.View Image

1. 
   Guest_ | Apr 06, 2000 12:46am | #4

   *Mike,

   That device is no where near the card method of drawing an ellipse. That device draws a true arc, one that has a radius, not an ellipse which is defined by two focus points. Sorry.

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

1. 
   Guest_ | Apr 06, 2000 12:49am | #5

   *Ryan,

   Nice animation but, it looks like it's drawing a gable roof. . .;-}

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

2. 
   Guest_ | Apr 06, 2000 01:11am | #6

   *Ryan inspired me with his animated gif. Thought I'd give a jab at trying to show the old 3 nails and a string trick.View ImageYou start out with a rectangle the same size you want your elipse.Then you draw lines at halfway, both directions.Then you measure from point 'A', (intersection of the two lines), to point 'B' intersection.Go to point 'X' intersection, and using the measurement you got from 'A-B', make a mark at point 'Y', (yellow dot). Make a corresponding mark at the other yellow dot.Now, drive a nail in a short way at both of the yellow marks, and at intersection 'A'.Wrap a string around all 3 nails and tie back to itself.Dislodge the string from the nail at intersection 'A'. Put a pencil inside the string circle and draw the string tight by moving the pencil toward the outside of the rectangle. Keeping the string tight and the pencil in the straight upright position, move the pencil in the elipse shape. You will have a perfect elipse drawn to the size of the rectangle.

2. 
   Jim_K_ | Apr 06, 2000 01:11am | #7

   *
   Nice animation, Ryan. As you show, this tool makes half a football, not necessarily an ellipse.

   A good way to make a true ellipse uses a piece of string and two spikes. We had several ellipses on our house, and the engineer specified a point A and a point B along the major axis. He also specified the string length. Tie the ends to the spikes, hold it taut with a pencil, and trace a true ellipse. The string will be longer than the gap be/t the spikes, meaning the ends of the ellipse fall _beyond_ the spikes, something not possible with the tool mentioned.

   To be really picky, an ellipse is, "the locus of points for which the sum of the distances from each point to two fixed points is equal." [Dictionary.com] With the tool mentioned, the sum of the distances changes as you draw the arc, making it not an ellipse.

   Try spikes a foot apart and a 16" string. Lengthen the string and you get a "rounder" ellipse. Shorten the gap be/t the spikes and the same thing happens, right up to the point where the spikes touch and you get a perfect circle. In practice, making sure the spikes don't move and the string doesn't stretch makes a big diff in the precision of the ellipse.

   The trick with all of this is calculating the placement of the spikes and the length of the string, of course. The formulas are nasty.

   Cheers,

   Jim

3. 
   Guest_ | Apr 06, 2000 01:33am | #8

   *

   Luka,

   These drawings might help explain what your trying to say. If not, try this. . .

   View Image

   © 1999-2000

   "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."

   Aristotle

1. 
   Guest_ | Apr 06, 2000 01:49am | #9

   *Joe,Thank you, and I really appreciate the way you can work that cad program, and can get your mind wrapped around all those numbers.But I have to say that I have had a good laugh because of the way you took my simplified version and made it all difficult again. I have to sign off on this one for now, my brain itches.View Image

1. 
   Guest_ | Apr 06, 2000 02:40am | #10

   *The animation is not exactly scientific proof of anything. I am sure of this: (let me see if I can put it in words that make sense)With this device, as your pencil aproaches one of the nails, the direction the pencil travels becomes more and more vertical.As you actually reach a nail, the pencil is moving (just for that instant) exactly up and down. This is like an elipse in that at the ends of the major axis, a line tangent to the curve would be verticle.This is not like a segment of a circle.

1. 
   Guest_ | Apr 06, 2000 02:42am | #11

   *I think I've pretty much proven that this tool is perfect for drawing stop signs.

4. 
   BillR_ | Apr 06, 2000 04:52am | #12

   *
   Ryan C:

   Great question. The resulting curve is not an arc and is not an ellipse. The easiest way to show it is not an ellipse is to see that at the fixed points, the curve is not smooth, and is not tangent to a line perpendicular to the axis of the two fixed points. Ellipses are.

   To get an equation for the line start with the distance between the two points, call it 2a. Call the fixed angle m at point p. We are looking for the locus of points p. Drop a line through p perpendicular to the 2a line. For any point x along the 2a line between the fixed points we are looking for the height y.

   Now m is made up of two angles on either side of the line y. One angle has (a-x)/y as a tangent and the other has (a+x)/y as a tangent. So m = atan((a-x)/y) + atan((a+x)/y). We need to solve for y. We can use the trigonometric identity tan(p+q) = (tanp + tanq)/ (1-tanp*tanq), applied to tan(m) = tan (atan..+atan..). That brings us to

   y^2 * tan(m) - a*y + (x^2-a^2)*tan(m) = 0

   which can be solved for y by the binomial theorem. The result isn't very pretty but it works. Can't say as I've ever run into this curve before.

   Somebody better check my math.

5. 
   Guest_ | Apr 06, 2000 05:28am | #13

   *
   like i said... it sounds like a version of the card method , especially based on RyanC's last description...

   in which case it does draw a true ellipse ..so..

   if someone cud actually post a picture of the tool, maybe we cud decide if it IS based on the card method

   but, short of seeing the actual tool. i guess this is destined to remain another one of life's little mysteries...

   b ahhh...sweet mystery of life.....

1. 
   Guest_ | Apr 06, 2000 12:32pm | #14

   *

   You boys are just kidding with these answers right?

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

1. 
   Guest_ | Apr 06, 2000 01:18pm | #15

   *I like Bill R's approach. I was looking for a mathmatical approach instead of a graphical. I'm off to work but I'll sit down this evening and see if I agree with your math.In Joe's defense. I did the same sketch he did and measured the angle of this tool as it moves along the circle. The angles are printed. Of course, I'd expect slight variations in the angle because of errors in my cad program. If this thing doesn't draw a circle, it draws something darn close. If it vary's from a circle, it seems to do so at the fixed points. Somebody said "football" maybe they're right.View Image

6. 
   BillR_ | Apr 06, 2000 08:53pm | #16

   *
   My daughter, a freshman in high school, reminded me that she had the same problem in homework a couple weeks ago. It's an arc. When she shows me her textbook I'll see how they did it. A few posts ago I gave a complicated equation. Equations of that form are equations of circles. Sorry to get so complicated. Joe and the others who said it's an arc are right.

1. 
   jim_evers | Apr 06, 2000 10:34pm | #17

   *BillRI think the middle term of your formula should be -2ay. You are missing the 2. Anyway, using trig formula tan(m)=tan(2n)=2tan(n)/(1-tan^2(n))=2ah/(h^2-a^2). Solve your formula for tan(m)=2ay/(y^2-a^2+x^2). Set those two tan(m) formulas equal and get hy^2-(h^2-a^2)y+h(x^2-a^2)=0. Solve for y using quadratic formula: y=(h^2-a^2+sqr((h^2-a^2)^2-4h^2(x^2-a^2)))/2h. This is the equation of the curve that angle device makes where h=height of curve from its horizontal base and a is half the horizontal span. Not a circle unless h=a. Not an ellipse unless it's a circle. Nasty formula but neat math. Thanks for helping me get there. jim evers

7. 
   Guest_ | Apr 06, 2000 11:09pm | #18

   *

   Well. Go figure, I never woulda thunk it!

   View Image

   © 1999-2000

   "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."

   Aristotle

8. 
   jim_evers | Apr 07, 2000 04:37pm | #19

   *
   Yes it is an arc of a circle. The equation above is correct and is the equation of a circle. I had the blinders on and was visualizing a semicircle (when h=a) or half an ellipse. Joe's diagram makes the geometry clear, since inscribed angles intercepting the same arc of a circle are equal. Case closed. jim evers

9. 
   Guest_ | Apr 12, 2000 10:09pm | #20

   *
   this is one of my favorite threads, and i don't know from Adam about the formulas.....

   in another user group they were discussing how to divide an ellipse into equal parts..thot i'd throw it out as a brain teaser...(certainly not for me... i'll have to do it graphically like the polygon solution>

   b here it is..

   >> >>How can I divide a ellipse in exact equal parts ?
   >> >How many parts? Equal in what sense (area, length, etc)?
   >
   >>length of the 'arc', the number of parts changes for different situations.
   >
   >A quick note from this mathematician:
   >
   >The length of a section of an elliptic arc is one of the well-known
   >impossible integrals. It's even given a name - an elliptic integral.
   >
   >Any solution for an arbitrary number of segments will involve numerical
   >integration and some limit of approximation.
   >
   >It's not a simple problem.
   >--
   >
   >-> From the U S of A, the only socialist country that refuses to admit it. <-
   
   Convert to polygons (conversion res as high as you dare). Then draw a
   vertical line next to and duplicate along path wit a fixed number of
   duplicates. Not the real thing, but it comes close.

   Vriendelijke groeten,

   Gerard Jonker

1. 
   Guest_ | Apr 13, 2000 05:39am | #21

   *Ryan, don't pay joe no attention. your stop sign drawer made this more clear to me than all that high falutent math talk did. Then again, I like when joe talks math.Pete

10. 
    BillR_ | Apr 13, 2000 05:03pm | #22

    *
    I don't see the geometric proof that the curve is an arc anywhere in this thread, so here it is from my daughter's textbook.

    Show a circle with center O and two points A and B and an arc AB between them. Angle m with vertex at O has the same measure as the angle measure of the arc. Draw a line through B and O to the other side of the circle, intersecting at point C. Make a new angle n from A to C then (through O) to B. It is easy to prove that n = 1/2 of m.

    Now take any point C' on the circle making a new angle p with A and B. Draw a line through the center O and you have two cases like what is shown above, either additive or subtractive.

    So in fact if you set the tool to angle a, the angle measure of the arc that you draw is (360 deg - 2a). And the center is easy to find with perpendicular bisectors.

11. 
    Guest_ | Apr 13, 2000 06:23pm | #23

    *
    Bill,
    I did the sketch, I don't see how this has anything to do with to tool in question. If you've got it strait in your head, your probably right but talk to me like I'm four.

12. 
    BillR_ | Apr 13, 2000 08:21pm | #24

    *
    Sorry. I never attached a drawing before, but I'll try here.

    The aim is to show that with A and B as fixed points on a circle, and point C anywhere on the same circle, all the angles

13. 
    Guest_ | Apr 13, 2000 09:17pm | #25

    *

    Just wondering if anyone clicked on the link that I provided in the very first reply to this thread?

    View Image

    © 1999-2000

    "The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it."

    Aristotle

1. 
   Guest_ | Apr 14, 2000 12:13am | #26

   *Bill R:nice. I think I'm convinced. However, I'd still like to see it done mathematically instead of geometrically. I know you took a stab at it. I did too. I came up with a different formula (or at least a different form of yours) but I also could only come up with y as a function of the angle.I would like to see the formula of a circle derived from this tool with y given as a function of x. My formula, like yours included many arctangents. Ugly. Probably reducable to a circle but I'm just not that good anymore.Get your daughter on it ;) And while she's at it, send her over here to program my VCR.

14. 
    jim_evers | Apr 14, 2000 03:41pm | #27

    *
    Ryan C
    The equation is in an earlier post by me -- on April 6. That equation is derived by finding the locus of points which form a curve h units high in the middle and have a span of 2a. Then, since the equation generated is of (but not in)the form (x-h)^2 + (y-k)^2 = r^2 (a circle with center(h,k) and radius r) it must be an arc of a circle. Some of us were looking for a semi-ellipse or a semi-circle in earlier posts and it is neither unless h=a.

15. 
    Guest_ | Apr 14, 2000 10:23pm | #28

    *

    Jim,

    The formula you have described is the "Distance formula".

    d = SQRT( (x2-x1)² + (y2-y1)² )

    Which gives way to the formula you have expressed, which is the standard equation of a circle.

    (x-h)² + (y-k)² = r²

    Which still is in its more recognizable form just the Pythagorean Theorem

    a² + b² = c²

    The reason why this is so is because C(h,k) P(x,y) = r or (CP)² = r² where C is the center of any circle and P is any point on that circle. This will produce the familiar right triangle CPP'.

    
    
    View Image

    © 1999-2000

    "Whenever, therefore, people are deceived and form opinions wide of the truth, it is clear that the error has slid into their minds through the medium of certain resemblance's to that truth."

    Socrates

1. 
   Guest_ | Apr 15, 2000 02:31am | #29

   * To keep it simple always seems to be a problem around here. Why so many doubt that this device drew a section of an arc is just hard to believe, even after many good explanations.Expanding on the original graphic this one looks a bit like BillR's. One property of a circle is that if you connect any two points on the circle, such as points b and p making line bp and draw a line perpendicular to it such as line pe, this line will intersect a point on the circle that when point b is extended to intersect at e will make line be, this line will be equal to the diameter of that circle.If you were to move the line pe to the mid point of line bp it would go right through the center of the circle defining it radius C. This is were the equation R = ((((L/2)2)/H) + H) / 2 that I original gave comes from. That was a month ago. . . © 1999-2000"Whenever, therefore, people are deceived and form opinions wide of the truth, it is clear that the error has slid into their minds through the medium of certain resemblance's to that truth." Socrates

1. 
   Guest_ | Apr 15, 2000 02:53am | #30

   *b KISS...Joe..one way to keep it simple wud be IF...IFIF...someone wud post a pic of the device...i've waded thru 28 posts innumerable times, and i've seen a lot of graphics, and a lot of bad representations,BUTi've never seen the device...wot i find hard to believe is that a company wud actually market a device that is SUPPOSED to draw an ellipse, but really only draws arc segments... when actually , with a little card stock ..or aluminum sheet, i cud make a device (the ) that really does draw an ellipse....i don't think anyone is disagreeing here at all...but until i see the device that ryan was describing , i have no way of knowing what it is, or isn't capable of....ca peesh? (sic).. see, i think you've seen the device... and i haven'tb Thomashey, that's cool... why did my post come up in blue?

1. 
   Guest_ | Apr 15, 2000 03:06am | #31

   *Mike,

   Now if you were a "smart" guy instead of "simple" one, you would have did what I did the first time I read the original post, MAKE ONE. Instead you keep falling on your face about the CARD METHOD. . .

   I posted a picture of my Senco nails and in the back ground you can see where I used the DEVICE to draw the arc.

   Just in case you missed it. Here's the picture again.

   You might want to stick to frogger. . . You make this way to easy ;-}

   View Image © 1999-2000"Whenever, therefore, people are deceived and form opinions wide of the truth, it is clear that the error has slid into their minds through the medium of certain resemblance's to that truth." Socrates

1. 
   Guest_ | Apr 15, 2000 03:17am | #32

   *b ya see joe... it's just as i thot.. u haven't seen ryan's device either...u mad a supposition that u knew wot ryan was describing... and i'm still waitin.now i no wot ur's looks like, and yur right ...i've seen the card method..and i've seen the string method....and yur method ain't either...hah, hah, hahbut if i want to draw some arcs, u cud cut yurs up and put it in 1 of those overnight mail paks and i cud glue it bac together,, and draw lots of arcs.....slow nite, ain't it?yur simple buddy, Pogostill miss em, don't ya ? (.)

2. 
   Guest_ | Apr 15, 2000 03:28am | #33

   *Mike,

   Yeah, you see what happens when you wait to long. . . you go from Kermit to Pogo. HaHa

   View Image © 1999-2000"Whenever, therefore, people are deceived and form opinions wide of the truth, it is clear that the error has slid into their minds through the medium of certain resemblance's to that truth." Socrates

16. 
    Michael_Selman | Apr 19, 2000 04:35am | #34

    *
    I myself use a length of 3/4 inch pvc pipe. Held down at both ends with 8d nails . I then raise the pipe up to the heighth that I need and trace it out. No string, no device, no hassle.

17. 
    Guest_ | Apr 19, 2000 05:24am | #35

    *
    I like the rock and leaded glass method myself.

18. 
    steve_bell | Apr 19, 2000 06:30pm | #36

    *
    Ahh, the elliptical dilema rears its ugly head, Fine Woodworking publishes a best of series, in this is the Best of Tips and Tricks.THe opening chapter details the fundamentals of measuring and marking, towards the end of the chapter you will find an article that details a run and rise method that boat builders use to create elliptical arches. The run is half the width of said ellipse, the rise is the point where the ellipse intersects the apex of ellipse,to either create an oval or change planes(meeting of a window or door head and side) these to points define the axis I don;t have a drawing program here but try to follow,these principle will draw and copy any ellipse the run/rise create a 90degree angle

    a

    b c

    a gauge(flt stick) about six inches longer than the dim. of bc is your drawing impliment with your dims. layed out ontis stick point c is the very end,that is where your pencil will mark the ellipse.

    from point "c" measure back the distance of "a"

    b a c

    now point b and a will need to have pins(trammel points,nails) this device; used in conjuction with a square(frame square,corner of a ply panel, any 90degree angle) the points b a pulled slowly along a right angle will allow point "c" to trace the outline of your ellipse.This may need clarification or a trial and error sesion,but who designs elliptical details expecting piece of cake mentality!This method has worked well as you can confidence ,I have used this method to design router jig to produce multiple casings and applied mouldings that were not part of window/door package,duh. THat Tips and Techniques is more clear and must have

19. 
    Guest_ | Apr 20, 2000 01:14am | #37

    *
    and no ellipse.....it's an arc

1. 
   Guest_ | Apr 20, 2000 01:18am | #38

   *steve, if u read post #2 of this thread and display the *jpg file i posted , i think you will see a graphic explanation of what you described...

1. 
   Guest_ | Apr 25, 2000 07:00am | #39

   *Okay, maybe we are smart--maybe not. Before we start trying to prove how to trisect any angle with a compass and straight edge, try this one: You have twelve identically-looking balls, eleven are the same weight and the twelfth is a different weight. Use a balance scale three times to find the odd ball and tell whether it is lighter or heavier. Good luck!

1. 
   Guest_ | Apr 26, 2000 11:33pm | #40

   *Joe Fusco...or anybody..How much does the Earth curve in one hundred feet?....near the stream wondering why the water runs only one way...aj

1. 
   Guest_ | Apr 27, 2000 03:22am | #41

   *Jack ,I think the earth curves .00027 degrees in 100 ft. but that's just a guess by eye,I could be off a little.Vince

2. 
   Guest_ | Apr 27, 2000 11:46pm | #42

   *Hi Vince...So if I build a three hundred foot long ranch house....and get it perfectly level...How much would the middle rise above the ends??near the stream, scratchin my head on that one...aj

3. 
   Guest_ | Apr 27, 2000 11:51pm | #43

   *AJ, if it's perfectly level ? None, is this a trick question? Vince

4. 
   Guest_ | Apr 27, 2000 11:57pm | #44

   *Vince...perfectly level means that the floor follows the arc of the Earth...so if I shot a laser from end to end...it would show that the middle of the ranch was high by the amount of the Earths curve which is some basic Trig that I have long since forgotton...near the stream,ajI'm off to dinner and to deliver some clay...hoping for the trig lesson upon return...Vince...Joe....Ken....?

5. 
   Guest_ | Apr 28, 2000 12:29am | #45

   *AJ,

   Where you getting this stuff from? The best way to "describe" level is to say that it is the line that is tangent to the point you are standing/measuring at. Since there is only one tangent line to any point, no two points in theory are level on the earth.

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

6. 
   Guest_ | Apr 28, 2000 05:13pm | #46

   *geeesh.. aj.. even fuscoe got that one right...it don't follow the arc of the earth.. it's a tangent line..if you had a POWERFUL,powerful, laser level..((((like my PL3)))))you would project a level line tangent to the tripod or point it was set on...so the 300 foot foundation would be level to the tolerance of the instrument....

7. 
   Guest_ | Apr 28, 2000 10:21pm | #47

   *Hey Kermit,

   I thought you would have been able to tell the good folks why I was "wrong" in my reply, you being really good in math and all but, I guess ellipses is what you know best. . .HaHaHa.

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

8. 
   Guest_ | Apr 28, 2000 11:34pm | #48

   *no joe, pullin yur chain is wat i no best, hah, hah, hahPogo

9. 
   Guest_ | Apr 29, 2000 12:13am | #49

   *Kermit,

   Nah, you're much better at "pullin'" something else! HAHAHA HEHEHE

   So. . . do you have any idea what's wrong with my statement, or are you still winging it?

   View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

10. 
    Guest_ | Apr 29, 2000 05:40am | #50

    *Well, I'm no mathematician, but it seems to me that if you pour the foundation so that the middle of it is dipping below the "sphere" of the earth, and that the two ends on the "sphere" are level with each other, then the line isn't tangent, but something else, the name of which escapes me.Just guessing,Rich Beckman

11. 
    Guest_ | Apr 29, 2000 05:56am | #51

    *On a circle you can have an infinite number of "level" lines(tangents), but only two can be parallel(the opposite tangent-180 deg. from its partner). It gets a little more complex with a sphere....John

12. 
    Guest_ | Apr 29, 2000 12:36pm | #52

    *John,

    You're close. After I posted my reply I realized that my remarks where in reference to a circle (two dimensional) and not a sphere (three dimensional).

    Basically the problem with my statements was that on a circle there is only one tangent line from any point on the surface of the circle and there is an infinite number of points on the surface.

    On a sphere there is an infinite number of tangent lines from any point on the surface of the sphere. The circle on the left describes what you stated and the sphere on the right what I have described.

    View Image © 1999-2000"The first step towards vice is to shroud innocent actions in mystery, and whoever likes to conceal something sooner or later has reason to conceal it." Aristotle

13. 
    Guest_ | Apr 29, 2000 01:53pm | #53

    *All right, we all know that aj is asking how much the middle of a foundation will rise if it follows the curve of the earth. I'm not even sure that I agree with the idea that a level line is necessarily a straight line. It's too rediculous to debate because it's all about semantics which is certainly imperfect but If somebody told me that a line that followed the curve of the earth was level at every point along it's length, I'd say sure, that makes sense.To the mathematician, a line is perfectly straight. To everybody else a line doesn't have to be. The yellow line on the road, the helical line around my pillsbury biscuits, or the line I wait in to get tickets. Semantics.

14. 
    Guest_ | Apr 29, 2000 11:00pm | #54

    *i'll stick wit mine...the level line is the plane projected by the leveling instrument..if yur werkin with a T-2 theodoloite, it's different than werkin with a builders transit..but anyways the plane we're talki abot is apx. 300 feet depending on wether yu set up your instrument in the middle or on one of the ends..the only correction would be for refraction...and the accuracy of the instrument..now that would be if the foundation were laid out with a ((((Plane Survey))) where the effects of teh earth's curvature are neglected...if the foundation were laid out with a (((Geodetic survey)))then it implies a reference spheroid assuming the data of the size and shape of the earth..but if i set my instrument up and turn elevations and set point all around the instrument at 150 ft.. all of those points and the instrument would be on the same level(((PLANE))).

15. 
    Guest_ | May 01, 2000 01:44am | #55

    *

    Well boy's, I guess you pretty much have summed it up. . .

    View Image © 1999-2000"The only difference between graffiti and philosophy is the word fuck." Unknown

16. 
    Guest_ | May 01, 2000 05:52am | #56

    *if joe's agreein with us , i'd start lookin over my shoulder...be afraid.... be very afraid

17. 
    Guest_ | May 01, 2000 02:06pm | #57

    *Just checking in boys....This has been a dusy....heha for ten minutes!.(I read slow)....I still would like to know the difference from plane the foundation level tangent line strikes from the curving surface of mother earth....The math boys...near the stream enjoying this stream,aj

18. 
    Guest_ | May 01, 2000 05:07pm | #58

    *I would like to know just what it is AJ wants to know...the english, boys...by the pond,Rich Beckman

19. 
    Guest_ | May 01, 2000 11:14pm | #59

    *This is really a simple question once you get what I am trying to describe....The Earth surface curves...On large scale civil engineering projects, it's relative and has to be considered...on a home it doesn't...For example; I read up on laser levels this winter and found that the accuracy listed by one of the companies was mainly limited by the curving of the Earth...which the laser canb not account for...{Huge buildings, (say a Walmart that was ten miles long,) having to be continuosly tangent to the Earth to "appear" to be built level to the site could not be "layed out" with a straight laser shooting)....the math boys....near the obtuse stream, but hey give us the math!aj

20. 
    Guest_ | May 01, 2000 11:58pm | #60

    *sorry aj, i don't do no stinkin math...and i don't do no ten mile wal-marts.. maybe three mile islands...

21. 
    Guest_ | May 02, 2000 04:31am | #61

    *Hey! I built an island once...........

22. 
    Guest_ | May 02, 2000 08:22am | #62

    *So did I, but the first tin can that came down the gutter knocked all my pebbles over and my weeble got wet.

23. 
    Guest_ | May 02, 2000 01:57pm | #63

    *This is a simple math challenge boys...keep your skirts down and send in your math solutions...near the stream seeing a solution in one of you...aj

24. 
    Guest_ | May 02, 2000 06:31pm | #64

    *Hey AJ, I think I've got it.If your building is 300 ft long, it will need to rise about .0005354 feet in the middle or about .00004461 inches. You'll need a smaller tape measure.

25. 
    Guest_ | May 02, 2000 08:12pm | #65

    *Hey! I have a skirt too!PS. Anyone seen that tampon ad with the kilted crazies ?

26. 
    Guest_ | May 03, 2000 12:41am | #66

    *Ryan...you da man!!!....now please someone post the math......near the stream, waiting and waiting and....aj

27. 
    Guest_ | May 03, 2000 01:05pm | #67

    *Alright, here's how I did it.I think I remeber the earth is 25K miles around the equator. Divide by pi to get the diameter and then divide by 2 to get the radius. 25000/pi=7958, 7958/2=3979mi convert from miles to feet with 5280 ft in a mile.3979*5280= 21,009,120ft (radius of earth)Now to the grafic:View ImageI took the liberty of approximating this 300' (only used half to find the difference at center) chunk of curst as a straight line. This let me use a right triangle to do the calculation.from a² + b² = c² with a = radius, b=150' or crust, and c= unknown, we solve for c and get c= 21009120.0005354 ft which is .0005354 more than the radius of the earth.Now, this isn't exactly the same thing as how much the curve of the earth rises, it's actually how much the curve of the earth falls from level in 150 feet. But I think it's gonna give the same number.I can't believe I got the same number both times I did it.

28. 
    Guest_ | May 04, 2000 05:59am | #68

    *Superb Ryan....Joe...time to check Ryan's math....near the stream thinkin there's more than one guy sharp enough to work this out....who's game out there in lurker land?Which of uses ain't wearin a skirt tonight, near the stream??aj

29. 
    Guest_ | May 04, 2000 07:32am | #69

    *AJ, I can tell you that the earth is 21,600 Nautical Miles around the poles and that I am not wearing my skirt tonight ! By the OceanPS. Nautical Mile. Length of arc of 1' of meridian in latitude of position in measurement. Value varies between 6046.4 ft. in eqator and 6107.8 ft. at Poles. A standard of 6080 ft.is used in log registrations and practical navigation. The International Nautical Mile = 1852 metres. Sea Mile.

30. 
    Guest_ | May 05, 2000 01:21am | #70

    *Ok....I'm standing with my eyes just above water in calm water at Buzzerd's Bay, cooling down from my last Vball game. How many sea miles will I be able to possibly see a hundred foot tall ship before it disapears over the horizon...?near the bay,aj

31. 
    Guest_ | May 05, 2000 01:29am | #71

    *AJ

    59. something or other miles (land). The next time you build something 60 miles long . . . Let me know. . . . . . .

    View Image © 1999-2000"The only difference between graffiti and philosophy is the word fuck." Unknown

32. 
    Guest_ | May 05, 2000 01:49am | #72

    *Well Joe...you know with the internet and all the homes are gettin mighty big...When ys gonna build a Fusco home bigger than Gates has?near the stream,aj...I wonder if MS browsers automatically scan for the word Gates?...true freedom in the future is goin underground for sure...soon!

33. 
    Guest_ | May 05, 2000 06:54am | #73

    *AJ, That would be 10 NM + a wee bit because we don't want to get into the math of what happens if your eye is half submerged, nor do we want you to drown whilst waiting for tall shiips !From "Modern Chartwork" 1963 4th edition The distance in nautical miles of the sea horizon from an observer whose height of eye is "H" feet above sea level is given by the formula 1.15 x root of "H" (dang don't have a scientific keyboard). If an observer, whose height of eye is "H" feet above sea level, can just see a light, the height of which is "H" feet above sea level, the distance he is off the light will be equal to the sum of the distances of the sea horizon for each of these heights. EXAMPLE : An observer, whose height of eye is 25 feet above the sea, can just see a light, the height of which is known to be 100 feet above sea level. How far is he from the light?Distance in miles=1.15 x root of 25 + 1.15 x root of 100 " " " =1.15(root of 25+root of 100) " " " =1.15(5+10) " " " =17.25 NM Please note the example is for 25 feet above sea level because that was the example in the book and it actually makes a more realistic and usefull way of looking at the question. By the sea and typing to much But I could be wrong !

34. 
    Guest_ | May 05, 2000 07:25am | #74

    *there are already too many ranch burgers - but your 300 foot one sounds like a BIG WOPPER

35. 
    Guest_ | May 05, 2000 07:32am | #75

    *what if you live in a valley?

36. 
    Guest_ | May 05, 2000 08:02am | #76

    *Re: EllipsesI usually just draw the eliptical element in CAD and plot out a full-size template for the builder with plumb & level line ... it's usually appreciated. Up to 3' high x as long as necessary. Fits in nicely with not having to do 'the stinkin' math.'

37. 
    Guest_ | May 05, 2000 02:42pm | #77

    *Alrighty Novy 7....Thanks for the post by the sea...I may have to plug a Target warehouse length building into this to see how many eighth inches the warehouse floor will rise in it's center from plane to follow tangent to the Earth...Thinking next about the observation influence factor of modern physics...near the stream,ajHave we mentioned fractals lately?....

38. 
    Guest_ | May 05, 2000 02:45pm | #78

    *Jeff...how bout fullsize plans for the whole house, and big pins to(o)...then we could build the walls, etc. exactly as you want them... just like the old balsa model airplane days...Even you, jeff could build it!near the stream,aj

39. 
    Guest_ | May 05, 2000 02:55pm | #79

    *Mike...Joe and you got it exactly wrong....but I fo-got to tell ya back awhile ago...Now read all the thread and tell me why?....or maybe you already realised it and wimpered away...near the stream...thinking that if I made a building to enclose a thousand mile long lap pool...that if I soley set up a transit once tangent to the Earth, then layed out and built the sucker, and attempted to fill it from the middle...their would never be a drop of water at the ends....All laser planed streams run to the center...aj

40. 
    Guest_ | May 05, 2000 04:41pm | #80

    *aj... (33.1).. its really ben rainin a lot up ther , huh?yur yust chngn the parameters ain't ya..once it wuz a 300 ft buildin...now it's a 1000 mile lap pool.. well why don't ya start swimmin?if i use a water level... or i use a transit.. or i use a laser... the bldg's gonna lay out the same..now u wanna break this down into the two problems yur really disgustin,, like wats the curvature of teh earth.. and what is a level plane.. then we can talk..if u evr get back frm yur swim..BTW ..bb don't lik my spellin, i hadnt noticed, do u think its a regional thing ?o & BTW.. congrats on 1 of the most succesful thread hijacs on recordKermit

41. 
    Guest_ | May 05, 2000 06:55pm | #81

    *i if i use a water level... or i use a transit.. or i use a laser... the bldg's gonna lay out the same.. Sure, if you're building a regular building. But if you're building something so big that the curve of the earth needs to be accounted for...not so.A lazer will give a straight line. Okay the lazer will curve some because of earth's gravity but not much. We'll call it a straight line.The transit: straight line. Still using light just like the lazer.Water level: curves with the earth. A big container of water...lets call it the ocean...is curved.

20. 
    jim_evers | May 05, 2000 07:09pm | #82

    *
    Ryan,
    Just looking at your calculations from post 49. The center of the building 300 ft long rises .0005354 ft above center. That is .006428 inches. Isn't that about the thickness of a piece of paper?
    jim evers

21. 
    Guest_ | May 05, 2000 07:51pm | #83

    *
    ryan.. yur gonna take the 1000 mile swim too, eh?

    why is the water level curving.... cud it be gravity?

    why is the laser curving?.. i don't think it's gravity.. i thionk it might be refraction..

    b but hey, whadda i no?

    did ya file the seer down on yur semi-automatic yet?

1. 
   Guest_ | May 05, 2000 11:27pm | #84

   *Jim,When I took a machining class the instructor told us that a piece of paper is roughly .003". That would make you 100% off. ; } And in this thread, that would be almost unforgivable.John

1. 
   Guest_ | May 06, 2000 01:18am | #85

   *Yes, the water curves because of gravity. At different places, the gravity is pulling in different directions: all toward the center of the earth. The lazer will bend because of gravity and will be refracted by the atmosphere. I didn't consider the atmosphere but I'm sure it would have a greater influence than gravity. But, light is effected by gravity. Light has mass. I'm sure that the effect of gravity on the lazer would be negligable (as if the .00005354 ft isn't)

1. 
   Guest_ | May 06, 2000 05:04pm | #86

   *I tried that once, but they had to be rolled around a 32 foot length of ductile iron sewer pipe to be delivered to the jobsite and well ... no one could lift them. It worked out fine, though, 'cause they spent exactly as much time looking at them as ever :).

1. 
   Guest_ | May 06, 2000 08:48pm | #87

   *> how many eighth inches the warehouse floor will rise in it's center from plane to follow tangent to the Earth... My math is weak, but "follow tangent to the Earth" makes no sense to me here. To me "follow the arc of the Earth" makes more sense in this context. Is it just me?Rich Beckman

2. 
   Guest_ | May 08, 2000 02:33pm | #89

   *An arc is made up of a series of tangent points...near the stream watching her rise above my local tangent points...ajps..My tennis courts are built disregarding the curve of the Earth...what a hack..

22. 
    jim_evers | May 08, 2000 02:33pm | #88

    *
    A couple of weeks ago Ryan C posted a question regarding the use of a tool to trace out an ellipse. It made use of an adjustable angle whose sides rest on two points and the vertex of the angle is supposed to strike out an ellipse. I did this on graph paper and can tell you that an ellipse the tool does not make. If the angle is 90 then the curve is a circle. If the angle is close to 90 degrees, then the curve is close to a circle. The further away from 90 the angle gets, the more the curve does not resemble an ellipse, especially at the outer reaches of the major axis. I would not use this gadget to strike out an ellipse, but I would like to know what shape this thing really makes. Does anyone know?