This datalayer is part of a group of layers used for research in the Ipswich River Watershed. This is slope data for the study area. Taken from the source elevation tile data which 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). We then used the DEM to produce the slope model using the SURFACE module in IDRISI.
This datalayer was produced as part of a research project concerning the Ipswich River Watershed.
3-meter contours created from Digital Terrain Model (DTM) data points collected during the production of 1:5,000 Black and White Digital Orthophoto images
Process_Date: before August 2001
Ipswich watershed slope derived from DEMHorizontal Coordinate System Name:NAD 1983 StatePlane Massachusetts Mainland FIPS 2001
Datum: D North American 1983
Reference Ellipsoid: Name: GRS 1980 Semi Axis: 6378137.0
Projection Name : Lambert Conformal Conic
Number of bands : 1
Raster Origin : Lower Left
Rows : 1152
Columns : 1692
Cell Geometry :pixel
Maintenance and Update Frequency:None.
8/1/2019 corrected lat/long inversion for Ipswich Watershed boundary box.