ArcGIS .asc file and Geoprocessing Tools - Values are Changing

[DebbieH]

I have an .asc grid file that I would like to be able to clip, convert to an ESRI grid, and also use the Set Null tool on. However, when I try to use any of these tools, the Values in the grid file change. I am so confused. For example, in the original .asc grid file, the max value is 1.478. When I run a the Clip too, the max comes out at 5.8928. All the cell values change (and it isn't applying a meters to feet conversion, I checked that out). Has anyone run into something like this?

[DanPatterson]

What is the coordinate system? and was it specified?

What was used for specifying the cell size, extent  and whether a snap raster was used?

are you assessing the maximum based on the map legend or have you looked at the before and after historgrams?

[DebbieH · Accepted solution]

Dan, you hit the nail on the head. The TOC is actually not displaying the max correctly for the .asc grid. Even after I built pyramids, it is still off.  The range that results after I use geoprocessing tools is the correct range. Displaying unique values in the raster layer properties confirms this.

[SteveLynch]

What happens when you use CopyRaster and create for example a fgdb raster from the .asc raster?