Monday, January 24, 2011

ArcGIS Bug: Certain img files yield incorrect cell count totals

A coworker and I just ran into a problem with the reported cell counts of an img file. We were performing a mosaic using an img and a grid and we were checking the cell counts of the final raster and they seemed much too low. Come to find out, the totals for the img appear to be wrong.

We used the copy raster tool to copy to a grid. The cell count totals for the new grid are much lower than the original img. We copied the grid back to an img. The new img has the same cell count totals as the grid.

We hypothesize that there is some corrupted state an img can exist in, such that ArcGIS cannot properly count the cell totals, but it can still properly convert to different raster types.

Example File:
http://www.mrlc.gov/multizone_download.php?zone=6  (download "Landcover zip file")


ArcGIS Versions:
9.3, 10.0

References:
  1. http://forums.arcgis.com/threads/3672-Raster-Calculator-reduces-the-count-number?p=71411#post71411

1 comment:

  1. In general, any pixel value with count > 2.1 billion will show a wrong count in the attribute table. Usually it is a negative number or missing altogether. ESRI has known about this for years and not fixed it.

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