"SteveB" fired this volley in news:1n5vp6-jfb2.ln1
@news.infowest.com:
Use a planimeter to do it, or print a picture of it to some sort of scale
on graph paper, then break it up into the smallest polygons (of the same
shape and size) you can.
Here's a model of a planimeter in software you can DRAW a picture into.
Also, several CAD programs like Rhino have the capabilities to solve for
areas of irregular shapes.
LLoyd
You don't. You need more information.
Divide it into segments - two semicircles for the ends, and groups
of triangles or trapezoids for the middle, get their area, and
add.
What is it you're trying to accomplish?
Good Luck!
Rich
Old-timey method is to take an overhead photo of the whole thing, take
a picture of a known area at the same height, cut out both pictures,
weigh both pictures, then you can calculate the area of the unknown
from the weight. It worked for years for figuring land areas next to
rivers that frequently changed course. You can't do it just by
measuring the perimeter unless it's a regular figure, circle,
semicircle, triangle, hexagon, or whatever.
Stan
Fix a rule to the side of the pool.
Bail out one (or more) 55 gallon drums full from the pool
Area per inch change per drum is approx 88.23 sq ft.
Walk around the perimeter feeling happy :-)
Mark Rand
RTFM
What a strange world this is becoming.
Computer power to the people - but you have to be a calculus
student or programmer to understand it.
I went through a dozen pages on Google looking for a simple
explanation of Simpson's Approximation. But found nothing
that did not assume that your could already do integrals
(using their software!).
Let me give it a try, Steve.
Working from perimeter alone - on a curved object?
That would be tough.
What you are trying to do is come up with an estimate of the
area under a curve (integral).
So, we need some dimensions - but how do we measure curves?
That's easy if we break the curves down into a series of rectangles.
(Trapaziods work too and would be more accurate, but start square)
Assuming you can measure across the pool...length and width.
Decide on an interval (D). The smaller the interval, the more
accurate the answer will be, but the more work you will have to do.
Think of D as the longest Distance involved divided into an even
number of pieces. Ten divisions is a good starting point.
That makes D be the length divided by 10.
So if the pool is 10 feet long, then D would be 1. Ok so far?
Next, we want the distance across the pool (perpendicular to the
long distance).
From that we can easily calculate the area of each rectangle.
Refer to these as Area(n).
Now, simply sum the areas.
Volume can be worked similarly, but we'll leave that for next time.
Richard
It is actually simple.
Have a helper on the other end of the pool.
Draw a straight line along the pool.
Start with the edge of the pool.
Go in 1 foot steps along that straight line.
Measure width across the pool perpendicularly to that line, for every
such foot step.
Add those widths.
This is the area of the pool in square feet.
It will be relatively accurate.
i
In general, you can't. If you kick in the side of a 5 gallon bucket,
how much does it hold? The rim length hasn't changed.
In this particular case, call the manufacturer or installer.
jsw
I suspect that comes from Iggy understanding Calculus and the integral.
formatting link
Integrals appear in many practical situations. Consider a swimming pool. If it is
rectangular, then from its length, width, and depth we can easily determine the
volume of
water it can contain (to fill it), the area of its surface (to cover it), and
the length
of its edge (to rope it). But if it is oval with a rounded bottom, all of these
quantities
call for integrals. Practical approximations may suffice for such trivial
examples, but
precision engineering (of any discipline) requires exact and rigorous values for
these
elements.
My greatest regret in high school is that I didn't wise up and start on the
right track to
take Calculus.
Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
Yes. OTOH, there are many other things that I do not know very
well. I wanted to try cutting inside thread (6 TPI) and for now I
postponed it because I do not know too many things about it to do it.
This newsgroup is a great learning place.
I think that anyone who starts messing with machines, quickly realized
that there are great advantages to knowing Descartes coordinate
systems, trigonometry, and possibly some calculus. From physics,
mechanics and thermodynamics are useful also.
i
Print the plan on a rectangle of paper and glue it on a piece
of cardboard the same size. Measure it and find its area.
Weigh it as close as you can and find the weight per area.
Cut out the shape and weigh that. Divide that weight by
the weight per area to get the area.
The pool area should be less than the area of a circle
of the same circumference as the pool perimeter.
Or bail it out and count the gallons and then convert to square feet of
water
Gunner
GUNNER'S PRAYER:
"God grant me the serenity to accept the people
that don't need to get shot, the courage to shoot
the people that need shooting and the wisdom to know the difference.
And if need be, the skill to get it done before I have to reload."
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