Creating Closed Polygons for Drainage Area Map (Help)

This is my first post to this newsgroup, so please forgive me if this
topic has been discussed before.

I have a drainage area map that I have created with plines in AutoCAD
2005 Map (which includes the Land Development package). The drainage
areas are not closed polygons, however. Some of the lines cross, some
do not close, etc.

So, I figured out how to do a "clean up" of the drainge area map to
produce individual line segments and nodes. Now I need to create
separate polygons of each drainage area so I can get the area of each
one. I have over 200 separate areas, so the procedure needs to be
automated to do the whole map at once.

I tried the "create polygons" procedure in Map, but with no success. I
keep getting error messages. Does anyone have a link to the exact,
step-by-step procedure on how to do this, or any tips on what I might
be doing wrong?

After all the closed polygons are created, I can use the "Parcel"
command or "area" command to query the polygons for their areas.

Thanks so much for your help.

-Pholus

 

HiHo;
In "Phil Kreiker", "The Cad Cookbook collection", he has a program
called "MakePoly" that joins a series of lines, arcs, 2d polylines, ect.
into one polyline. You might look at www.cadalyst.com in the
"Get the code" section, for a similar program.

 

Thanks for the suggestion. I'll definitely check into this, but isn't
there a built-in process in AutoCAD which will accomplish the same
thing without having to use an outside program or routine? Thanks
again.

-Pholus

 

I don't understand how this came to be the case. Why not just make closed
polylines in the first place?
Is it impossible for some reason? Is the drawing 3D?

 

Michael asks:
"I don't understand how this came to be the case. Why not just make
closed
polylines in the first place?
Is it impossible for some reason? Is the drawing 3D? "

Pholus replies:
The drainage area divides were created with individual polylines by
first delineating the overall watershed area. This is a closed
polygon, the outer limits. But then the individual sub-drainage areas
inside the watershed were created with single polylines without looping
each one. For example two sub-drainage areas share a common boundary
line. To create looped sub-areas, you would have to trace over the
same common boundary lines, which is a duplication of effort. I
understood that I could create the sub-areas this way, with single
polylines, and that the topology function could be used to create
separate closed or looped polygons from the individidual polylines.
The function should work this way, but I just can't seem to get it to
work properly for some reason.

-Pholus

 

Sounds like the BOUNDARY command might come in handy here...
___

 

You beat me to it, Paul.
That's definitely the way to do this if I understand the problem correctly.

 

Pholus,

Go to http://tovna.com
Under download section they have 30day evaluation of GBOUND II 2006.
It's the best program for polygons that i know.
I hope it helps.

Regards

 

the address in the previous post should be:
http://www.tovna.com
sorry