How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve

"SteveB" fired this volley in news:1n5vp6-jfb2.ln1
@news.infowest.com:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

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

Lloyd E. Sponenburgh writes:

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.

Use a bitmap editor to trap and count pixels with a histogram.
All you need is a plan view digital image.

On Wed, 07 Oct 2009 13:10:58 -0600, SteveB wrote:

How do I figure the area of a pool from the perimeter?

You don't. You need more information.

It is a kidney
shaped (exaggerated) pool.

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

"Rich Grise" wrote in message
news
On Wed, 07 Oct 2009 13:10:58 -0600, SteveB wrote:

How do I figure the area of a pool from the perimeter?

You don't. You need more information.

It is a kidney
shaped (exaggerated) pool.

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

To figure the surface area having only the perimeter as a known variable.

Steve

On Wed, 07 Oct 2009 14:31:56 -0600, SteveB wrote:
"Rich Grise" wrote in message
news
On Wed, 07 Oct 2009 13:10:58 -0600, SteveB wrote:

How do I figure the area of a pool from the perimeter?

You don't. You need more information.

It is a kidney
shaped (exaggerated) pool.

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?

To figure the surface area having only the perimeter as a known variable.

Then you're pretty much out of luck.

A round pool will have a lot more surface area than a long skinny pool
with the same perimeter.

Sorry,
Rich

Rich Grise fired this volley in
news

Then you're pretty much out of luck.

Rich! Bull! That's _exactly_ what a planimeter does for a living!

C'mon... this isn't like most of your posts.

LLoyd

Lloyd E. Sponenburgh wrote:
Rich Grise fired this volley in
news
Then you're pretty much out of luck.

Rich! Bull! That's _exactly_ what a planimeter does for a living!

C'mon... this isn't like most of your posts.

LLoyd

A minor exception offered here...

A planimeter measures AREA by tracing around the object.

It doesn't use the perimeter measurement, just it's shape.

Is that important?

A circle, with diameter of 1 has a C of 3.14159 thingies.

It also has an area of 0.786475 square thingies (A = Pi R^2).

C = 3.14159 A = 0.786475


A SQUARE with the same area would have sides of length equal to the
square root of the area of the circle.

Sqrt(0.786475) = 0.886834257

Sum of four sides that length (perimeter of the square) is 3.547337029.

NOT 3.14159


Conclusion:
The circumference of a square and a circle of equal area is NOT the same.

So I don't think having the perimeter length is not going to solve the OP's
area question.


Richard

On Wed, 07 Oct 2009 19:12:19 -0500, Lloyd E. Sponenburgh wrote:

Rich Grise fired this volley in
news

Then you're pretty much out of luck.

Rich! Bull! That's _exactly_ what a planimeter does for a living!

C'mon... this isn't like most of your posts.

But that's already been suggested. Steve wants to measure the perimeter,
square it, multiply it by a constant, and get the area.

But every possible shape has it's own constant, so he's out of luck.

--
www.wescottdesign.com

Lloyd E. Sponenburgh wrote:
Rich Grise fired this volley in
news
Then you're pretty much out of luck.

Rich! Bull! That's _exactly_ what a planimeter does for a living!

No, it integrates surface area while measuring BOTH perimeter and angle
traveled from a single point, simultaneously. That makes a big
difference, although I still don't know exactly how they work. But,
they require you to stick a pin in the paper at one point and not move
it until you've traced the entire perimeter.

Jon

On Oct 7, 4:31*pm, "SteveB" wrote:

To figure the surface area having only the perimeter as a known variable.

Steve

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

On Wed, 7 Oct 2009 14:39:16 -0700 (PDT), Jim Wilkins
wrote:

On Oct 7, 4:31*pm, "SteveB" wrote:

To figure the surface area having only the perimeter as a known variable.

Steve

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


Or bail it out and count the gallons and then convert to square feet of
water

G

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."


0

Let the Record show that Gunner Asch on
or about Wed, 07 Oct 2009 16:15:26 -0700 did write/type or cause to
appear in rec.crafts.metalworking the following:
On Wed, 7 Oct 2009 14:39:16 -0700 (PDT), Jim Wilkins
wrote:

On Oct 7, 4:31*pm, "SteveB" wrote:

To figure the surface area having only the perimeter as a known variable.

Steve

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


Or bail it out and count the gallons and then convert to square feet of
water

Fill a 55 gallon drum with water and seal it. Roll it into the
pool. Repeat until you can measure an increase in water level.
Estimate the volume of the barrels.


pyotr
-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

On Wed, 07 Oct 2009 14:31:56 -0600, SteveB wrote:

"Rich Grise" wrote in message
news
On Wed, 07 Oct 2009 13:10:58 -0600, SteveB wrote:

How do I figure the area of a pool from the perimeter?

You don't. You need more information.

It is a kidney
shaped (exaggerated) pool.

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

To figure the surface area having only the perimeter as a known
variable.

Measure the perimeter, square the measurement, and multiply it by the
perimeter-to-area constant for the shape in question. For a square pool
the constant is 1/16, for a circular pool the constant is 1/(4*pi), for
an infinitely skinny pool the constant is 0. For your pool you'll have
to consult an appropriate handbook, or calculate it.

To find the correct constant for the shape of your pool, first calculate
it's surface area, then divide that area by the perimeter squared. Then
you'll have the correct constant, and you can calculate your pool surface
area -- or the surface area of any other pool with an exactly similar
shape -- just by knowing the perimeter.

--
www.wescottdesign.com

On Oct 7, 1:10*pm, "SteveB" wrote:
How do I figure the area of a pool from the perimeter? *It is a kidney
shaped (exaggerated) pool.

Steve

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

fired this volley in news:656dee88-c74d-4919-a95a-
:

You can't do it just by
measuring the perimeter unless it's a regular figure, circle,
semicircle, triangle, hexagon, or whatever.


WRONG! Check out what planimeters do! (geeesh!)

LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
fired this volley in news:656dee88-c74d-4919-a95a-
:

You can't do it just by
measuring the perimeter unless it's a regular figure, circle,
semicircle, triangle, hexagon, or whatever.


WRONG! Check out what planimeters do! (geeesh!)

LLoyd

I Googled planimeter, and came up with
http://en.wikipedia.org/wiki/Planimeter

It is as plain as the nose on one's face, but I'll just continue my own ways
of estimating.

Steve

On Wed, 07 Oct 2009 20:23:18 -0600, SteveB wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
fired this volley in news:656dee88-c74d-4919-a95a-
:

You can't do it just by
measuring the perimeter unless it's a regular figure, circle,
semicircle, triangle, hexagon, or whatever.


WRONG! Check out what planimeters do! (geeesh!)

I Googled planimeter, and came up with
http://en.wikipedia.org/wiki/Planimeter

So did I - and for a swimming pool, wouldn't that need one BIG HONKING
planimeter?

Thanks,
Rich

Rich Grise fired this volley in
news
So did I - and for a swimming pool, wouldn't that need one BIG HONKING
planimeter?


No..... one can do it from an aerial photo. And FWIW, even a BIG HONKING
planimeter is easy to make, easy to salvage afterwards.

LLoyd

On 2009-10-08, Rich Grise wrote:
On Wed, 07 Oct 2009 20:23:18 -0600, SteveB wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
fired this volley in news:656dee88-c74d-4919-a95a-
:

You can't do it just by
measuring the perimeter unless it's a regular figure, circle,
semicircle, triangle, hexagon, or whatever.


WRONG! Check out what planimeters do! (geeesh!)

I Googled planimeter, and came up with
http://en.wikipedia.org/wiki/Planimeter

So did I - and for a swimming pool, wouldn't that need one BIG HONKING
planimeter?

Or a nice aerial or satellite view from directly overhead and a
measurement between two known locations to calculate a scale factor.
Find the view, print it out, measure the distance between the two known
locations on the printout and the real world, then run the planimeter
around it and calculate the full scale area from the indicated area and
the scale factor.

I've got a nice old planimeter which I bought at a hamfest about
ten or fifteen years ago.

How much accuracy is needed for this project?

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

SteveB wrote:
How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



And then how do you estimate the volume of water, keeping mind the
bottom is curved to the drain.

On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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

"Mark Rand" wrote in message
...
On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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

Hey, Archimedes, what if a squirrel falls in the pool? g

Seriously, that would be fine if it's absolutely dead calm.

--
Ed Huntress

On Wed, 7 Oct 2009 16:43:55 -0400, "Ed Huntress"
wrote:


"Mark Rand" wrote in message
.. .
On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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

Hey, Archimedes, what if a squirrel falls in the pool? g

Seriously, that would be fine if it's absolutely dead calm.

Empty some of the oil from one of the 55gal drums onto the water ;-)



Mark Rand
RTFM

Ed Huntress wrote:

Hey, Archimedes, what if a squirrel falls in the pool? g


Then you better hope you can swim, because no one in their right mind
would throw you a life preserver.


--
The movie 'Deliverance' isn't a documentary!

On Wed, 07 Oct 2009 21:39:48 +0100, Mark Rand
wrote:

On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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


Not with a curved bottom.....


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."


0

On Wed, 07 Oct 2009 16:15:57 -0700, the infamous Gunner Asch
scrawled the following:

On Wed, 07 Oct 2009 21:39:48 +0100, Mark Rand
wrote:

On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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


Not with a curved bottom.....

Now who we talkin' about? horny grinne

--
For me, pragmatism is not enough. Nor is that fashionable word "consensus."

To me consensus seems to be the process of abandoning all beliefs,
principles, values and policies in search of something in which no one
believes, but to which no one objects; the process of avoiding the very
issues that have to be solved, merely because you cannot get agreement
on the way ahead. What great cause would have been fought and won under
the banner "I stand for consensus"?
--Margaret Thatcher (in a 1981 speech)

LJ sez: It's a good thing we have concensus on the case of Anthropogenic
Global Warming (kumbaya), isn't it?

On Oct 7, 7:15*pm, Gunner Asch wrote:
On Wed, 07 Oct 2009 21:39:48 +0100, Mark Rand
wrote:





On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? *It is a kidney
shaped (exaggerated) pool.

Steve

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

Not with a curved bottom.....


If you only drain a few drums from the pool, the bottom stays full and
thus has no bearing on the calculation (assuming that the sides are
parallel).

On Wed, 07 Oct 2009 16:15:57 -0700, Gunner Asch
wrote:

On Wed, 07 Oct 2009 21:39:48 +0100, Mark Rand
wrote:

On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve



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


Not with a curved bottom.....



You don't bail the water out of the bottom of the pool, you bail it out of the
top :-)


Mark Rand
RTFM

In article , Mark Rand wrote:
On Wed, 7 Oct 2009 13:10:58 -0600, "SteveB" wrote:

How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

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.
88.17
Walk around the perimeter feeling happy :-)

Clever. It would be easier still to *add* 55 gallons.

SteveB wrote:
How do I figure the area of a pool from the perimeter? It is a kidney
shaped (exaggerated) pool.

Steve




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

Ignoramus30647 wrote:
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.

Ig, that's a very good practical solution

On 2009-10-07, RBnDFW wrote:
Ignoramus30647 wrote:
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.

Ig, that's a very good practical solution

Thanks. This is basically numerican integration.

i

RBnDFW wrote:

Ignoramus30647 wrote:
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.

Ig, that's a very good practical solution

I suspect that comes from Iggy understanding Calculus and the integral.

http://en.wikipedia.org/wiki/Integral


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

On 2009-10-07, Wes wrote:
Add those widths.
This is the area of the pool in square feet.
It will be relatively accurate.
Ig, that's a very good practical solution

I suspect that comes from Iggy understanding Calculus and the integral.
http://en.wikipedia.org/wiki/Integral

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

Wes wrote:

My greatest regret in high school is that I didn't wise up and start on the right track to
take Calculus.


Never too late to get smart, Wes!



Richard

cavelamb wrote:
SteveB wrote:
How do I figure the area of a pool from the perimeter? It is a
kidney shaped (exaggerated) pool.

Steve




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!).

Because what you wanted was Simpson's rule.




--
John R. Carroll

John R. Carroll wrote:
cavelamb wrote:
SteveB wrote:
How do I figure the area of a pool from the perimeter? It is a
kidney shaped (exaggerated) pool.

Steve



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!).

Because what you wanted was Simpson's rule.




'scues me. John, but they are the same thing!

cavelamb wrote:
John R. Carroll wrote:
cavelamb wrote:
SteveB wrote:
How do I figure the area of a pool from the perimeter? It is a
kidney shaped (exaggerated) pool.

Steve



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!).

Because what you wanted was Simpson's rule.




'scues me. John, but they are the same thing!

Sort of.
Calculus takes the trigonometric solution, which you can do with paper and
pencil, one step further by taking the width of your segments to zero, or
actually, betwen zero and infinity.


--
John R. Carroll