Calculating an area in a closed polyline with an island

[stevedrew]

Trying calculate an area inside an exterior closed polyline that borders an interior closed polyline...

Please refer to attachment:

BPOLY.GIF

Using the hatch command, I can create hatch as shown in the above example and get the area using properties.

I have tried using bpoly with island detection but that does not seem to work either.

Bpoly command.GIF

Is there a Carlson command or AutoLISP program available?

Or am I missing something?

Thanks!

[ColC]

Try area by interior point. It has worked for me. If it doesn't work check that they are 2d lines.

[tstrickland]

An island doesn't work for me in Carlson Survey in area calculations, never has. It ignores the island and includes the area. Also with an island, the perimeter of the island is ignored.
I just manually subtract the inner area. I'm using 2009 embedded, haven't tried it in any newer versions.

[stevedrew]

[quote="ColC"]Try area by interior pTried the ptarea command e.g.

Tried ptarea e.g.:
Command: ptarea
Pick point inside area perimeter:

Polylines are 2D, Elevation = 0
Does not work....

[Dent Cermak]

QUICK FIX: Enclose your area with 2 separate closed polys. Pick a PI as a beginnjing poit and trace endpoint to endpoint half way around and then jump to an interior PI and trace back to the beginning PI. Make 2 separate closed polys. Then use the Area by closed polyline for each poly and add the areas together.

[stevedrew]

Got solution from:
Brian Harris
Technical Support
Carlson Software

You can use the "Area by Closed Polylines" routine under the Area/Layout pull-down. Toggle the "Single Area" and the "Prompt for Exclusion" options and hit OK. Follow the commandline prompts and you should be all set.

[Dent Cermak]

That's why we refer to Brian as "Brain" Harris areound here.

[ColC]

Sorry Steve,

I think my brain must have had a hole in it at the time. I had just had a similar situation to yours a month ago. I thought I had got it as I described but, I had actually used terry's method.
The "Brain" solution sounds like one to remember.(If I can just plug that hole of mine)