AutoCAD Map 3D General

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jens.kuegl
Posts: 20
Registered: ‎07-25-2011
Message 1 of 4 (351 Views)
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buffer a large data set

351 Views, 3 Replies
05-03-2012 03:12 AM

I am familiar with GIS but I am new to AutoCAD Map 2012.

 

I have 140,000 lines and 20,000 points.

 

I would like to have all points closer than 1 meter to a line.

 

This is what I tried to do:

  1. buffer the lines (_mapfdobuffercreate)
  2. overlay points and buffer (_MapGisOverLay) to get all points in the buffer area

 

This works well with a small amount of data.

 

But in step 1 I have to select all lines (140,000) with the mouse. When I try to select all lines with the mouse AutoCAD Map freezes after some minutes. Is there a way with AutoCAD to work on a “layer basis” and not on a “selection set basis”. Other GIS (ESRI, Quantum, …) work with a complete layer.

 

In this analysis I work with FDO Data (shp,sqlite,sdf). I have geometries, but no attribute data.

 

Any help would be greatly appreciated.

 

Regards

Jens

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Robert_Fritz
Posts: 160
Registered: ‎12-08-2011
Message 2 of 4 (348 Views)

Re: buffer a large data set

05-03-2012 04:28 AM in reply to: jens.kuegl

Hi Jens,

 

when Map asks you to select features you can usually use one of the options such as "all" - but unfortunately this doesn't seem to work for fdo features.

 

What you could try is to open the attribute table for the line feature class and choose  "select all" in "Options". When you then run the mapfdobuffercreate command all features will already be pre-selected.

 

Not sure if that will work or if you run into the same problem as before.

 

Good luck,

Rob

 

 

http://raumpatrouille3d.blogspot.ch/
*Expert Elite*
antoniovinci
Posts: 1,578
Registered: ‎06-03-2011
Message 3 of 4 (345 Views)

Re: buffer a large data set

05-03-2012 05:56 AM in reply to: jens.kuegl

To reduce dramatically the number of  lines, you could join 'em as polylines, by means of _MAPCLEAN (suboption DISSOLVE PSEUDO NODES).

Contributor
jens.kuegl
Posts: 20
Registered: ‎07-25-2011
Message 4 of 4 (330 Views)

Re: buffer a large data set

05-03-2012 08:37 AM in reply to: jens.kuegl

Thank you very much for your help. I have tried different approaches. But unfortunately, no one led to success with AutoCAD Map.

 

I set the visibility of the line-layer off. In the attribute table I selected the records. This is much faster than selecting objects in the map. Thanks for this tip Rob.

But when I tried this with all 140’000 records it took 45 minutes.

 

After all records were selected I started _ mapfdobuffercreate. I waited 10 minutes but the dialog box did not appear. So I've stopped at this point tying to create a buffer with AutoCAD Map.

 

Then I reduced the number of lines from 140’000 to 40’000 with _MAPCLEAN. Since _MAPCLEAN is not working with FDO I exported the FDO data to dwg and then back to FDO. I did not tried to select these 40’000 records in the attribute table.

 

I installed Quantum GIS (free). In Quantum GIS I was able to create a buffer (40’000 lines) in 10 seconds.

In Quantum GIS it took 5 seconds to select all points which are in the buffer (I tried this with AutoCAD: 10 minutes).

 

As I said, I am new to the AutoCAD Map World. My experience today is that AutoCAD Map is divided into two worlds: FDO and dwg. Not all tools seem to work the same in both worlds. In addition, the analysis tools seem to be good only for small amounts of data.

Quantum GIS was only a workaround today. I hope I manage to meet my future analyzes using AutoCAD.

Thanks for the help
Jens

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