topic cell statistics "ignore nodata values" not working in Data Management Questions

cell statistics "ignore nodata values" not working

KatieBlauvelt — Tue, 25 Sep 2012 17:41:03 GMT

Hello,

I have 12 geotiff rasters of the U.S., and I am trying to calculate a mean, median, max, and min raster from those 12 using cell statistics. There are some nodata values inside each raster, and I want the calculations to ignore these values (if the value of a pixel in each raster is: 7, 2, 4, 3, nodata, 1, 4, 2, nodata, 3, 1, nodata, then I would want the mean to be 9. Instead, if there is a nodata value in any of the 12 raster's, the output raster produces a nodata value. I have tried selecting the "ignore no data values" in cell statistics, but there is no difference; the output always produces a nodata value if there are any in the input rasters. I was wondering if anyone else had this issue, or if I am doing something wrong in the formatting of the nodata values.

Thank you!
Katie

Re: cell statistics "ignore nodata values" not working

KyleShannon — Thu, 27 Sep 2012 16:09:06 GMT

What is the no data value for the tifs?

Re: cell statistics "ignore nodata values" not working

KatieBlauvelt — Thu, 27 Sep 2012 18:35:53 GMT

I think I figured out the problem- Arc wasn't registering the nodata pixels as real nodata values. I created the nodata values as NaNs in ENVI, and even though when I opened them in Arc they would read as nodata values, it must not have been registering them as nodata in the cell statistics tool. I ended up using the setnull tool to define all my nodata values in Arc and trying the cell statistics again and this worked.

Thanks,
katie