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, 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).

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.

In article , (Edward A. Falk) wrote:
We have a winna!

It would be nice if you'd quote the post you're responding to so that other
people would know what the heck you're talking about...

On 2009-10-08, Doug Miller wrote:
In article , (Edward A. Falk) wrote:
We have a winna!

It would be nice if you'd quote the post you're responding to so that other
people would know what the heck you're talking about...

he was responding to my post.

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

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

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

Ignoramus19678 wrote:
On 2009-10-08, Doug Miller wrote:
In article , (Edward A. Falk) wrote:
We have a winna!

It would be nice if you'd quote the post you're responding to so that other
people would know what the heck you're talking about...

he was responding to my post.

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

Which was a simplified version of mine.
Hrump...

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 Thu, 8 Oct 2009 17:43:11 +0000 (UTC), (Edward A. Falk)
wrote:

In article ,
Doug Miller wrote:

It would be nice if you'd quote the post you're responding to so that other
people would know what the heck you're talking about...

Ahh, mea culpa. I've gotten too spoiled by a newsreader that threads
the posts and lets you know what post follows which, and lets you
easily see the previous post. Hadn't realized that not all newsreaders
do this.

Some of us prefer to limit the number of visible posts to less than a few tens
of thousands in any group. That means that we may well not display read posts.
relevant quoting is considered polite behaviour.


Mark Rand
RTFM

In article , (Edward A. Falk) wrote:
In article ,
Doug Miller wrote:

It would be nice if you'd quote the post you're responding to so that other
people would know what the heck you're talking about...

Ahh, mea culpa. I've gotten too spoiled by a newsreader that threads
the posts and lets you know what post follows which, and lets you
easily see the previous post. Hadn't realized that not all newsreaders
do this.

Mine does that. The problem is that I'd apparently already read the post you
replied to, and so it had disappeared before I got to yours.

Be aware, also, that *nothing* in the NNTP protocol guarantees that posts will
arrive at any particular news server in anything even faintly resembling the
sequence in which they were generated -- or, indeed, that they will arrive at
all.

In short, you cannot assume that the post you're replying to will be available
for reading by *anyone*, no matter what client software they're using. That's
why it's best practice to quote the relevant portion(s) of anything you reply
to.

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

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 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 ---

Doug Miller wrote:
In article ,
(Edward A. Falk) wrote:
In article ,
Doug Miller wrote:

It would be nice if you'd quote the post you're responding to so
that other people would know what the heck you're talking about...

Ahh, mea culpa. I've gotten too spoiled by a newsreader that threads
the posts and lets you know what post follows which, and lets you
easily see the previous post. Hadn't realized that not all
newsreaders do this.

Mine does that. The problem is that I'd apparently already read the
post you
replied to, and so it had disappeared before I got to yours.

Be aware, also, that *nothing* in the NNTP protocol guarantees that
posts will
arrive at any particular news server in anything even faintly
resembling the
sequence in which they were generated -- or, indeed, that they will
arrive at
all.

In short, you cannot assume that the post you're replying to will be
available
for reading by *anyone*, no matter what client software they're
using. That's
why it's best practice to quote the relevant portion(s) of anything
you reply
to.

Regardless, Iggi's solution is the common place implementation of Simpson's
Rule.
Marine Architects and Naval Engineer's know it, and French Curves, well.

--
John R. Carroll

Jon Elson wrote:
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.

Of course.
Analog or digital, you still have to set one of the bounds as a fixed point.
The other can be varied to suit, but not both.


--
John R. Carroll

DoN. Nichols wrote:
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.



Not that much, apparently.

SteveB's (OP) solution was to measure across the pool in several places,
average the widths and multiply by the length.

Close enough for non-financial government work.

cavelamb wrote:

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!




Periodically, I pick up a text book, periodically I set it back down. Seriously, if I
wasn't a wage slave and was part of the idle rich, I'd be in some college learning it.

Fwiw, I was pretty good solving trigonometric identities 15 years ago when I attended a
local college for a while. Only got a 3.5 in Trig but I was prouder of the 3.5 than the
4.0 in college algebra.

The gentlemen that taught the trig class, was a definite nerd, horn rimmed glasses,
trousers belted high but he was a good teacher, also head of the mathemetics department.

He mentioned he did his calculus problems as a student in ink

Wes

Wes wrote:
cavelamb wrote:

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!




Periodically, I pick up a text book, periodically I set it back down. Seriously, if I
wasn't a wage slave and was part of the idle rich, I'd be in some college learning it.

Fwiw, I was pretty good solving trigonometric identities 15 years ago when I attended a
local college for a while. Only got a 3.5 in Trig but I was prouder of the 3.5 than the
4.0 in college algebra.

The gentlemen that taught the trig class, was a definite nerd, horn rimmed glasses,
trousers belted high but he was a good teacher, also head of the mathemetics department.

He mentioned he did his calculus problems as a student in ink

Wes

There are many ways to study things.




http://www.understandingcalculus.com/
http://www.wannalearn.com/Academic_S...tics/Calculus/

On Fri, 09 Oct 2009 18:54:56 -0400, Wes wrote:

..

He mentioned he did his calculus problems as a student in ink

Wes

Ummm. How else does one do calculus problems then?


Expiring minds need to know :-)


Mark Rand(suddenly feeling old)
RTFM

Mark Rand fired this volley in
:

Expiring minds need to know :-)


hey! That's of MY sigs... and an original one, by me, for me! ('cept,
it's "Expiring minds WANT to know!")

LLoyd

-----------------
Cole's Axiom -- the total intelligence of the planet is constant. The
population is increasing exponentially.

Mark Rand wrote:
On Fri, 09 Oct 2009 18:54:56 -0400, Wes wrote:

.
He mentioned he did his calculus problems as a student in ink

Wes

Ummm. How else does one do calculus problems then?


Expiring minds need to know :-)


Mark Rand(suddenly feeling old)
RTFM



In one's head, of course!

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 Oct 8, 7:27*pm, cavelamb wrote:
DoN. Nichols wrote:
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
68.3.70...
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.

Not that much, apparently.

SteveB's (OP) solution was to measure across the pool in several places,
average the widths and multiply by the length.

Close enough for non-financial government work.-

A potentially accurate method is to divide the central area into
triangles and use Heron's formula in a spreadsheet:
http://mste.illinois.edu/dildine/heron/triarea.html

Assume the ends are semicircles and start the triangles one radius in
from the ends. The chord errors on the convex and concave sides may
partly compensate for each other if the curvatures are similar.

jsw

"John R. Carroll" wrote in message
...
Doug Miller wrote:
In article ,
(Edward A. Falk) wrote:
In article ,
Doug Miller wrote:

It would be nice if you'd quote the post you're responding to so
that other people would know what the heck you're talking about...

Ahh, mea culpa. I've gotten too spoiled by a newsreader that threads
the posts and lets you know what post follows which, and lets you
easily see the previous post. Hadn't realized that not all
newsreaders do this.

Mine does that. The problem is that I'd apparently already read the
post you
replied to, and so it had disappeared before I got to yours.

Be aware, also, that *nothing* in the NNTP protocol guarantees that
posts will
arrive at any particular news server in anything even faintly
resembling the
sequence in which they were generated -- or, indeed, that they will
arrive at
all.

In short, you cannot assume that the post you're replying to will be
available
for reading by *anyone*, no matter what client software they're
using. That's
why it's best practice to quote the relevant portion(s) of anything
you reply
to.

Regardless, Iggi's solution is the common place implementation of
Simpson's
Rule.
Marine Architects and Naval Engineer's know it, and French Curves, well.

--
John R. Carroll

We just did seven real estate studies in the last two days. My formula is
actually the best, even over Simpson's Rule. Take four widths, average,
then multiply by length.

This method is absolutely the best since mathematically, as on the pools, I
am expected to be plus or minus 25% accuracy.

Steve :-)

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
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

The site I use has measurement capabilities that are very accurate. At
times, I will click a 100' line on the screen, set a pair of dividers to
that length, then use the dividers to either estimate from the screen, or
from a printout.

Steve

"cavelamb" wrote in message
m...
DoN. Nichols wrote:
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.



Not that much, apparently.

SteveB's (OP) solution was to measure across the pool in several places,
average the widths and multiply by the length.

Close enough for non-financial government work.

And falls within the + or - 25% parameters set by the employer.

Steve

On Oct 10, 9:22*pm, "John R. Carroll" wrote:
SteveB wrote:
...
This method is absolutely the best since mathematically, as on the
pools, I am expected to be plus or minus 25% accuracy.
Steve *:-)

LOL
John R. Carroll

How do they know if you're wrong?

jsw

SteveB wrote:
"John R. Carroll" wrote in message
...
Doug Miller wrote:
In article ,
(Edward A. Falk) wrote:
In article ,
Doug Miller wrote:

It would be nice if you'd quote the post you're responding to so
that other people would know what the heck you're talking about...

Ahh, mea culpa. I've gotten too spoiled by a newsreader that
threads the posts and lets you know what post follows which, and
lets you easily see the previous post. Hadn't realized that not
all newsreaders do this.

Mine does that. The problem is that I'd apparently already read the
post you
replied to, and so it had disappeared before I got to yours.

Be aware, also, that *nothing* in the NNTP protocol guarantees that
posts will
arrive at any particular news server in anything even faintly
resembling the
sequence in which they were generated -- or, indeed, that they will
arrive at
all.

In short, you cannot assume that the post you're replying to will be
available
for reading by *anyone*, no matter what client software they're
using. That's
why it's best practice to quote the relevant portion(s) of anything
you reply
to.

Regardless, Iggi's solution is the common place implementation of
Simpson's
Rule.
Marine Architects and Naval Engineer's know it, and French Curves,
well.

--
John R. Carroll

We just did seven real estate studies in the last two days. My
formula is actually the best, even over Simpson's Rule. Take four
widths, average, then multiply by length.

This method is absolutely the best since mathematically, as on the
pools, I am expected to be plus or minus 25% accuracy.

Steve :-)

LOL


--
John R. Carroll