Need Area in Acres not Sq. Ft.

[Chris Mack]

I am a new autocad user and do a lot of area calulations of entities
which are all in sq ft. I need the areas in acres. I know that
there must be a lisp routine or tool that can make autocad give me all
areas in acres.

Anyone know how to do this.

Thanks in advance.

C Mack

[Chris Mack]

[Alan Williams]

In article: <310AB5...@linex.com> Chris Mack <cbm...@linex.com> writes:
> I am a new autocad user and do a lot of area calulations of entities
> which are all in sq ft. I need the areas in acres. I know that
> there must be a lisp routine or tool that can make autocad give me all
> areas in acres.

Hi
In case you don't know 640 acres = 1 sq mile
1 sq mile = (3*1760)^2 sq ft

Therefore 1 acre = 43560 sq ft

The following will convert sq ft to acres

(defun ft_acre ($ft)
(/ $ft 43560.0)
)

Or, why not add a conversion to the ACAD.UNT file and
then use CVUNIT?
--
Alan Williams al...@awol.demon.co.uk

[Dennis Shinn]

Chris Mack <cbm...@linex.com> wrote:

>I am a new autocad user and do a lot of area calulations of entities
>which are all in sq ft. I need the areas in acres.

Chris -

Try this. Note ... there is NO error checking. This is just a quick 'n dirty
response to the problem ..... (BTW - thanks to Alan (Williams) for the
conversion factor of SF to acres. Saved me looking it up (g))

(DeFun c:Acres ()
(GetArea)
(Cvt2Acres objarea)
(PstRslts)
)

(DeFun GetArea ()
(Prompt "\nSelect closed pline for area measurement...: ")
(Setq obj (EntSel))
(Command "AREA"
"ENTITY"
obj
)
(Setq objarea (GetVar "AREA"))
)

(DeFun Cvt2Acres (a)
(SetQ acres (/ a 43560.00)
)
)

(DeFun PstRslts ()
(Princ (StrCat
"\nEnclosed area in acres = "
(Rtos acres 2 2)
)
)
(Princ)
)
(Princ)

Dennis Shinn
Seattle AutoCAD User Group
SAUG-BBS [206] 644-7115 PCGNet 9:517/215
email: jee...@halcyon.com
BBS: dennis...@saug.wa.com

[Jeffrey R. Foster, Jr.]

Chris Mack wrote:
>
> I am a new autocad user and do a lot of area calulations of entities

> which are all in sq ft. I need the areas in acres. I know that
> there must be a lisp routine or tool that can make autocad give me all
> areas in acres.
>

> Anyone know how to do this.
>
> Thanks in advance.
>
> C Mack

Not sure if you got my message the other day, but visit my web page,
"http://www.mms.net/jfoster/index.htm" and go to the AutoCad
support/Autolisp page. I've posted two files here for you. One is
SF2ACRE.lsp which allows you to enter a number in square feet and it
returns the area in acres. The second file is SF2ACRE2.lsp. This one
will allow you to continue entering numbers in square feet until you
wish to quit. It also creates a file with the same name as the drawing
and has the extension, .s2a. In this file is stored the area in square
feet and in acres. The areas are also echoed to the screen.

Hope this helps.

TTYL,
Jeff Foster
CAD Designer, McKim & Creed Engineers, PA Raleigh, NC
"http://www.mms.net/jfoster/index.htm" <<-- Find AutoCad
support/Autolisp files here