jevans02

Raster divide error

Discussion created by jevans02 on May 11, 2010
I am trying to calculate a ratio of 48 binary rasters. I have written an AML to perform the analysis but there are a a few grids that the resulting float raster exceeds 32-bit addressing space. It is my understanding that ArcMap/Spatial Analyst can address larger rasters so I calculated the integer rasters (using focalsum) and tried to calculate the ratio in both raster calculator and Single Output Map Algebra (ArcToolbox). Both methods yield a float raster of a single value (0.5). I can subset the data to a smaller raster and get the correct results and I can recreate the problem on the other large datasets. Any ideas on why this is happening and a workaround that does not require subsetting the data?

Here is my statement for calculating the ratio (works on smaller rasters):
float((float([sum1]) / float([sum2])))

To calculate the rasters used above, starting with a binary raster:
tmp1 = CON(ingrd == 0, 1, 0)
sum1 = FOCALSUM(ingrd, circle, 1000)
  tmp3 = FOCALSUM(tmp1, circle, 1000)
sum2 = sum1 + tmp3

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