The following steps were used to process the 2011 National Elevation Dataset (NED):

* Mosaicked the 12 USGS NED rasters downloaded from the USGS NED
* Converted elevation values from 32-bit floating point to integer for the mosaic
* Ran a majorityfilter (2 times) on the mosaic
* Did a resample on the mosaic to degrade the cellsize to 0.000278 degrees
* Projected the mosaic to stateplane
* for the stateplane mosaic, converted the elevation values to feet using a factor of 3.280833 (rounded the elevations values by adding 0.5 to and then running the “Int” command on the dataset)
* Clipped the geographic mosaic data by 15’ USGS quadrangles (plus a 500-foot buffer) covering NH, then converted each to ascii
* Clipped the stateplane mosaic data by 15’ USGS quadrangles (plus a 500-foot buffer) covering NH, then converted each to ascii