Calculating Area

[bobsy852]

I've got a polyline around some fields on a map and need to find the exact area of these fields. Previosuly I've drawn a poly line around them and looked at the properties to find the area, simple!

 

however, this time I have multiple polylines making up boundaries etc and also there are some small fields within the larger fields that I need excluded from the area total. (they too have a small closed polyline around them)

Is it going to be a case of working it out manually by creating an individual poly line around each field, as well as 1 around the fields to exclude, then subtracting the smaller fields from the larger area?

Or will AutoCAD work out the area and exclude the smaller fields in the middle automatically because they have a boundary around them?

 

(To think of it simpler, think of a rectangle with a smaller rectangle inside it, and I need the area of the large rectangle minus the smaller one)

[alanjt]

With LT, you're left doing it the long way. Have you looked at the AREA command? It has a subtract object mode.

 

Out of curiosity, what happens when you type (getvar "userr1")?

[bobsy852]

With LT, you're left doing it the long way. Have you looked at the AREA command? It has a subtract object mode.

 

Out of curiosity, what happens when you type (getvar "userr1")?

 

will try the area command and let you know! that command reads "LISP command is not available"

[alanjt]

will try the area command and let you know! that command reads "LISP command is not available"

 

Oh yeah, you can't approach it that way.

Just type UserR1 and tell me what happens.

[bobsy852]

Oh yeah, you can't approach it that way.

Just type UserR1 and tell me what happens.

 

"enter new value for UserR1 :"

[alanjt]

Ahh, nevermind, won't work, but the AREA command will help you.

[bobsy852]

ok thanks!

[Coosbaylumber]

I used to copy or offset particular lines making up the figure by 1000,1000 from 0,0. And then create a whole new closed figure off to one area. Then, cite the area, tranlate the note back, and go on to next one (same routine).

 

Wm.

[CADformat]

use AREA command for that

[SEANT]

The Region entity is good for these types of calculations as well. A larger region can have multiple smaller regions removed via the Subtract command.

 

The Properties window will then report the adjusted area and perimeter.

[alanjt]

Playing around, you could make a button and use this to add the area of multiple objects.

 

^C^Carea;_o;\SETVAR;USERR1;$M=$(+,$(getvar,userr1),$(getvar,area));

[Pablo Ferral]

Hatches also feed back there area value to the properties pallette...

[bobsy852]

thanks everyone, i used the hatch properites and subtracted it manually! hopefully will pick up on all this macro and button creating skills the more i use CAD

 

another quick question while I'm here (nothing to do with areas though), when hatching and there is text, it usually leaves a space around the text to make it more readable!

However, for 1 of my notes it hasnt, and it's going to be a REAL pain to re-hatch it! is there any way to simulate the area of missing hatch?

 

thanks everyone!

[bobsy852]

haha it's ok everyone! sat here a couple of mintues and found it! WIPEOUT!

thanks for the help with the area caluclating

[SuperCAD]

Hatches also feed back there area value to the properties pallette...

 

That's what I do. Hatch all of my boundaries and select the hatch(es) to see the total area in my properties window.