This datalayer is part of a group of layers used for research in the Ipswich River Watershed. This is the aspect model for the study area. The source elevation tile data was provided on the MassGIS website www.state.ma.us/mgis/massgis.htm in ESRI-format shapefile format and imported into IDRISI software using the ShapeIdr command. The resulting vector elevation files were converted to raster format using successive Lineras macro commands. This has the effect of mosaicing the tiles as well. The raster image was filtered once using a low-pass (mean) filter, then masked to the Ipswich study area parameters (extent). The aspect map was created using the surface analysis module. This datalayer was produced as part of a research project concerning the Ipswich River Watershed.