A digital elevation model is a " a digital representation of ground surface topography or terrain". You can read more about it here.

The name of the dataset is "stpl_dem" and it is in GRID format. It is comprised by two folders:

It was obtained from http://seamless.usgs.gov/. In this website, we zoomed to the Hadley area and downloaded a 30 m DEM in geographical coordinates, datum NAD 83. The raster was reprojected to Mass State Plane Nad 83.

We have also included a shapefile vector image comprised by 6 files.

Obtained from http://www.mass.gov/mgis/eotroads.htm. The MassGIS road layer is made available tiled by town, we downloaded the one for the town of Hadley.

This layer is a Shapefile vector layer comprised by 4 files:

From http://www.mass.gov/mgis/zn.htm. The zoning layer is also tiled by town. Here is some relevant documentation obtained from the Mass GIS site:

“The MassGIS zoning data layer represents the boundaries of municipal zoning districts. 
 Because zoning is established at the town level, there is no standard district classification 
 across the state. Zoning district boundaries change frequently and MassGIS currently has no 
 formal process in place to regularly update these coverages. These data should therefore be 
 used for regional analysis only and not as official zoning maps. The town’s own official zoning 
 map and current copy of the by-law should be considered as the final word on zoning boundary 
 questions”. 

In short, these zones may not be completely up to date. This is an important issue that you should consider for the proposed problem: if this were a “real life” exercise, you should obtain the most updated zoning map directly from the town (but for the purpose of this exercise, we will go ahead and use this layer).

This is a Shapefile vector layer comprised by 6 files:

Extracted from a statewide layer of the town boundaries in Massachusetts: http://www.mass.gov/mgis/towns.htm.