Error: RDCONT - too many contour arcs, Bailing out of TOPOGRID

Error Message

TOPOGRID with a contour coverage returns the following error:

RDCONT - too many contour arcs
Bailing out of TOPOGRID


The contours are too dense for the output cell size specified. The number of contour lines being interpolated for a single output cell exceeds an internal estimate. The RDCONT routine reads arcs of the contour coverage. It estimates the size of internal programming arrays necessary to hold arc x,y coordinates. This estimate is based on the number of rows and columns of the output grid. There is no method to determine if this limit will be reached before running TOPOGRID.

Solution or Workaround

There are several possible solutions that can be implemented.

  • Decrease cell size with LATTICERESAMPLE (TIN) or RESAMPLE (Grid). If a larger cell size is needed after TOPOGRID, resampling can be performed on the output to increase cell size.
  • Rasterize smaller sections of the contour coverage using TOPOGRID subcommands XYZLIMITS and MARGIN.
  • Then CLIP the input contour coverage to smaller areas and TOPOGRID each contour subset individually. Then merge the TOPOGRID output sections with LATTICEMERGE (TIN), MERGE (Grid), or MOSAIC (Grid).

    The majority of the TOPOGRID error messages, such as TOO MANY CRITICAL POINTS, TOO MANY CONTOUR POINTS, or TOO MANY CONTOUR ARCS, are due to contour data that is too dense for the output resolution. TOPOGRID is being used as a resampling tool, for which it is not designed.

    See the "Informative messages" section of the TOPOGRID "Discussion" section in the ArcInfo online ArcDoc.