I'd like to ask about the value on following image.

This is an interpolated precipitation layer using IDW method in ArcGIS Desktop. On this layer, the values is like this:

precipitation layer

This is a raster image. After exporting the above layer into raster image, the value of the raster image has quite long decimals, specially the minimum value looks like this 4.43193612012e007.

Raster image

I have not only this image but also several images with similar value. When I calculate any equation on those images, output value from that calculation cannot be accepted, they were totally wrong.

So how can I reduce the decimal precision before or after exporting to raster?

  • Could you please describe the calculations you are making?
    – Aaron
    Jan 9, 2013 at 16:13
  • 1
    Is your problem only the display in the legend of too many decimals? This is the expected output for a interpolation surface
    – Gago-Silva
    Jan 9, 2013 at 16:19
  • @Aaron, here is an example of calculations I'm doing in ERDAS model maker. STACK SUM (( $n2_temp_2000 / 5.0 ) POWER 1.514)
    – user3063
    Jan 9, 2013 at 16:24
  • 1
    @A.R. I'm expecting the output with max of 3 decimals. But it is ok even it is the same decimals as interpolated layer.
    – user3063
    Jan 9, 2013 at 16:30
  • you made the IDW in ERDAS or ArcGIS ?
    – Gago-Silva
    Jan 9, 2013 at 16:31

1 Answer 1


Perhaps try multiplying by a constant and converting to integer. For example, use the Times tool to multiply by a constant representing the number of decimal places you wish to preserve (e.g. 1000 for three decimal places) and then truncate the remaining decimal values with the Int tool. Just be sure to remember that the values have been transformed in this way (or go a step further and convert back to a Float and then Divide by the constant).

All functions can be used inside the Raster Calculator to make this more efficient.

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