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Question

Creating contours from ERSI ASCII Grid (ASC) data?

  • September 12, 2013
  • 4 replies
  • 72 views

darren
Contributor
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I've been given some free to use Digital Surface and Digital Terrain models consisting of TIF, ETW, XML and ASC files. I was wondering whether I would be able to create contours (in TAB format) from the included ESRI ASCII Grid files (ASC)?

 

 

Apologies if this is a bit of a daft question, I'm a bit new to all of this :)

 

4 replies

takashi
Influencer
  • September 12, 2013
Hi Darren,

 

 

I would use the RasterCellCoercer to transform the raster to 3D points, and then create contours using the ContourGenerator.

 

 

Takashi

takashi
Influencer
  • September 12, 2013
You might be able to send the raster directly to POINTS/LINES port of the ContourGenerator.

 

 

ContourGenerator help: POINTS/LINES: These input features may be 2D or 3D, and may reside inside a raster, a point cloud, or other aggregate structures.

 

 

Takashi

darren
Contributor
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  • Author
  • Contributor
  • September 12, 2013
Hi Takashi,

 

 

Many thanks for the reply, it does look like you can send the raster directly to the ContourGenerator although I'm having a couple of issues with the output.

 

 

After experimenting with the parameters a little I've managed to generate a 5m contour file but am experiencing a large number of 'spikes'.  Could you suggest a way to minimise the spike effect?

 

 

Darren

 

 

 


fmelizard
Contributor
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  • Contributor
  • September 12, 2013
Hi,

 

It is possible that the spikes are actually locations of no data or extreme pixel values, I would try to resample the raster to possiy reduce nodata/extreme pixel values before generating the contours.

 

 

Itay

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