AutoCAD Map 3D General Discussion

AutoCAD Map 3D General Discussion

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Active Contributor
nomisc
Posts: 49
Registered: ‎11-02-2003
Message 1 of 21 (780 Views)

Converting 2D polylines with fixed width to polygons

780 Views, 20 Replies
09-11-2012 02:07 AM

Hi folks,

 

I've done a search and couldn't find a previous post similar to mine, so here it goes. Apologies if it has been asked

before.

I've been sent a series of CAD drawings in which the author has used global width to define the appearance of features. I need to import this into our GIS, which for reasons too complex to bother with won't import any attributes such as width. I don't want to lose the information recorded so was wondering if it's possible to create a closed polygon to represent the shape of the line. I guess something might be possible using buffering, but I can't figure out how to use the existing line width.

Ta

*Expert Elite*
antoniovinci
Posts: 1,750
Registered: ‎06-03-2011
Message 2 of 21 (777 Views)

Re: Converting 2D polylines with fixed width to polygons

09-11-2012 02:52 AM in reply to: nomisc

You have some ways to achieve it, either with wide polylines and donuts.
The cleverest one, in my opinion, is _MAPEXPORT to a linear shapefile, adding the following attribute:

 

Active Contributor
nomisc
Posts: 49
Registered: ‎11-02-2003
Message 3 of 21 (771 Views)

Re: Converting 2D polylines with fixed width to polygons

09-11-2012 03:33 AM in reply to: antoniovinci

Thanks for that, but I don't see how it has helped unless I've misunderstood what it does. When I import the shape file into our GIS it loses the attributes so I'm back to square one. I realise the problem lies with our GIS, but that's what I have to work with.

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antoniovinci
Posts: 1,750
Registered: ‎06-03-2011
Message 4 of 21 (768 Views)

Re: Converting 2D polylines with fixed width to polygons

09-11-2012 03:54 AM in reply to: nomisc

When you import in your Gis such a shapefile, you'll see the attribute Ewidth in its TOC (Table of Contents), which you can stylize your data with: you'd better speak with one of your Gis collegues, sir.

Active Contributor
nomisc
Posts: 49
Registered: ‎11-02-2003
Message 5 of 21 (722 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 08:59 AM in reply to: antoniovinci

Unfortunately when the data is imported, (for reasons I don't understand, but have to live with) all attribute data is stripped off so I need something that actually creates a polygon in CAD.:smileyfrustrated:

*Expert Elite*
Alfred.NESWADBA
Posts: 9,417
Registered: ‎06-29-2007
Message 6 of 21 (717 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 09:28 AM in reply to: nomisc

Hi,

 

what version of Map3D do you have?

 

- alfred -

-------------------------------------------------------------------------
Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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Active Contributor
nomisc
Posts: 49
Registered: ‎11-02-2003
Message 7 of 21 (713 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 09:53 AM in reply to: nomisc

Hi Alfred,

 

It's Map3D 2011

*Expert Elite*
antoniovinci
Posts: 1,750
Registered: ‎06-03-2011
Message 8 of 21 (708 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 10:41 AM in reply to: nomisc

nomisc wrote:

Unfortunately when the data is imported ... all attribute data is stripped off

 

They are stripped off 'cause you forget to force the creation of Object Data (please Alfred, show him how, since at home I'm acadless...)

Active Contributor
nomisc
Posts: 49
Registered: ‎11-02-2003
Message 9 of 21 (704 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 10:53 AM in reply to: antoniovinci

No, it's not as simple as that. I know how to attach data and in all other situations it's fine. The problem is that the GIS is part of the corporate network and when data is added in the format that it needs to be added so that the linkages with the rest of the database occur all data apart from the layer, which has to be the UID of the object being linked is lost. Please, this is not a GIS issue, or rather it is, but one that cannot be fixed. Please can you accept that the issue cannot be resolved by having attributes attached to a line. Unless you want to start discussions with our corporate GIS I need a way to do this and create a polygon in CAD? If the answer is no then I'll accept it, but it just strikes me that it ought to be possible. Sorry if I'm getting frustrated.

*Expert Elite*
Alfred.NESWADBA
Posts: 9,417
Registered: ‎06-29-2007
Message 10 of 21 (696 Views)

Re: Converting 2D polylines with fixed width to polygons

09-17-2012 12:11 PM in reply to: nomisc

Hi,

 

now I'm unsure what the goal behind really is, sorry (and don't get more frustrated!)

 

First you wrote that you get dwg-files using polylines with polyline-widths where you like to convert the polyine with width to a polygon that shows the border around the polyline-width (at least that was how I understood the original post).

For that my workflow would be:

  • create a topology from these lines
  • query this topology with the buffer-analysis and use the the half of the polyline-globalwidth as buffer-distance
  • finished

What I now don't understand is the last message with:

>> when data is added in the format that it needs to be added

>> so that the linkages with the rest of the database

What is stored in the drawing with the polyline (with globalwidhts) that fits to your final GIS-structure using UID's?

Either you have already ID's assigned to the polylines, then I don't see where these data is destroyed on the way it get's converted from line-topo to polygon-topo ... but maybe I'm missing something now.

 

Look to the video (done with 2010, so your 2011 can do that also) and let us know how this is useful (or not) for you.

 

- alfred -

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Alfred NESWADBA
Ingenieur Studio HOLLAUS ... www.hollaus.at
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