To View DEMs in ArcView 3.x:

- Turn on Spatial Analyst Extension.
- In File menu, select IMPORT DATA SOURCE.
- Import File Type: USGS DEM.
- Select DEM.
- Save in appropriate directory.
- Add to View.

To View DEMs in ArcMap:

- Open ArcToolbox.
- Expand Conversion Tools.
- Expand Import to Raster.
- Choose DEM to Grid.
- Browse to the .dem file in the USGS DEM field.  
  Choose Integer in Conversion Options.  
  Browse to the location you want to save the 
  grid in the Output grid field.
- Now open ArcMap and bring in the grid.

****************************************************************

These data files contain USGS 30-meter Digital Elevation
Models (DEMs) that have been re-processed by Complex Systems
Research Center, University of New Hampshire, to conform to
GRANIT database standards. All processing was done over the 
period January - March, 1999. 

The key elements of the data processing included:

	- reprojecting the spatial data from UTM meters 
        (Zone 18/19), NAD27 to NH State Plane feet, Zone 
        4676, NAD83.

	- standardizing all Z-values to feet

The specific steps applied to each data file included the following:

1.  Data for each quad was retrieved from the USGS web site 
    in STDS format as a tarred, compressed (gzipped) file.

	(http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/7_min_dem/states/NH.html)


2.  The single files were uncompressed and untarred into
    quad-specific directories.

	(usage: gunzip -c 30.2.nnnn.tar.gz | tar -xpvf - )


3.  In Imagine:
	a)  Load the *IDEN.DDF data to create the *.img file
	b)  Convert the *.img file to an Arc/Info compatible GRID

4.  In Arc/Info:
	a)  Run STDSINFO and record relevant parameters
	b)  Run PROJECTDEFINE on the grid
	c)  Check cell size of each grid, and standardize to
	    to meters if necessary
	d)  Reproject the GRID to NH State Plane feet, NAD83
	e)  Convert Z-units from meters to feet, if necessary
	f)  Convert all edge values from their default value
	    of -32767 to "no data"
	g)  Run LATTICEDEM to convert GRID back to ASCII DEM
	    format

Data for 201 of the 213 quadrangles in the state was processed in
the above manner.  Of these 201, data for the 21 quads listed below
required conversion of Z-units from meters to feet:


	11	Bosebuck Mtn.			
	16	Wilsons Mills
	28	Umbagog Lake South
	33	Success Pond
	35	Lancaster West				
	177	Peterborough North			
	181	Manchester South				
	182	Derry			
	183	Sandown			
	184	Kingston	
	185	Exeter
	186	Hampton
	197	Nashua North
	198	Windham
	199	Salem Depot
	200	Haverhill
	201	Newburyport West
	202	Newburyport East
	211	Nashua South
	212	Lowell
	213	Lawrence

Data is presently unavailable for the 12 quads listed below:

	12	Monadnock Mtn, VT-NH
	34	Miles Pond
	41	Barnet East
	42	Lower Waterford
	59	Newbury
	68	Fryeburg
	79	Brownfield
	90	Kezar Falls
	92	Enfield
	102	West Newfield
	103	Hartland **
	115	Great East Lake

	** Data for quad 103 was posted to the current USGS web site.
	However, upon processing the data at Complex Systems
	Research Center, it was determined that a significant
	Y-shift was present in the data and it was deemed
	to be unusable in conjunction with the remainder
	of quads.