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RE: AI-GEOSTATS: DEM-interpolation method

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  • Steve Zoraster
    A problem with contour vertices - point values is that most information encoded in the contours is thrown away. The correct solution is to maintain the
    Message 1 of 2 , Mar 3, 2004
      A problem with contour vertices -> point values is that most information
      encoded in the contours is thrown away.

      The "correct" solution is to maintain the input data as contours. For each
      grid node build search lines parallel to the rows and to the columns of the
      DEM, and interpolate from the nearest contour elevations found in those two
      searches. If necessary, add searches offset by 45 degrees from rows and
      columns.

      The trick to making this practical is to note that finding all contour
      crossings of, for example, a horizontal search line for a single DEM row can
      be done before any node interpolation is performed. Some DEM smoothing
      required. And special case software for DEM nodes inside peaks or valleys.

      This method was used by USGS during the 1980s to build DEMs from contours
      scanned off 1/24,000 scale quads. I suspect they are still using it. I do
      not know of any algorithms outside the petroleum industry.

      Steven Zoraster

      -----Original Message-----
      From: Ines



      Dear member list
      I used contour line and few elevation points to generate a DEM, the first
      interpolator that I used was been the TIN interpolator but the RMS was been
      not very good, so I converted all nodes of the contour lines into elevation
      points and I used them to produce many model based on IDW, RBS and KRIGING
      interpolators.
      Using these interpolators I obtained a good results.

      My question is:
      it has meaning to convert all node of the contour lines in points and use
      them to generate a DEM with different interpoators that ask points as input
      data?



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