Contact the Geospatial Centre
Dana Porter Library, Room 328
University of Waterloo Library
Waterloo, Ontario N2L 3G1
Email: librarygeo@uwaterloo.ca
Description
The provincial Digital Elevation Model (DEM) is a high resolution raster data set covering the province of Ontario. It has been interpolated from the Natural Resources and Values Information System (NRVIS) contour and water virtual flow data sets collected and updated from January 1976 to January 2002. Cell resolution is 10 metres in southern Ontario and 20 metres in northern Ontario. The dataset consists of 150 tiles. In southern Ontario each tile covers approximately 150 km by 100 km. To determine the appropriate tile number(s) for your area, please consult the Indexes to Natural Resources and Values Information System (NRVIS) Digital Elevation Model (DEM) tiles .
Spatial reference and data type
These data are available in Universal Transverse Mercator (UTM) coordinates; horizontal datum is North America Datum (NAD) 83. The files are stored in United States Geological Survey (USGS) DEM format.
This DEM data requires some manipulation in order to create surfaces and contours. Please see the Geospatial Centre Guide Working with DEM-DTM in ArcGIS (PDF) for a brief outline on how to use these data in ArcGIS. Please see images below for examples of surface and contour outputs created using DEM data.
Data access
In order to access these data sets, please visit the Geospatial Centre Reference Desk during reference hours. Library reference staff are available to provide further information about these data sets and to deliver data upon request. Under the terms of the Library's license agreement, these data sets are for use by students, faculty, and staff at the University of Waterloo only.
Data manipulation and storage
There are public workstations in the Geospatial Centre that provide access to both ArcGIS and ArcView software programs, program extensions and data manipulation utilities. 3-D Analyst allows 3-D display with the ArcScene application using GRID data structures. You must have the 3-D Analyst extension turned on to display/create/analyze data in TIN format.
Patrons may use the Geograpahic Information System (GIS) software in the library to view and manipulate the data. UWaterloo faculty, students and staff may copy these data to other media (for example: CD, DVD or Zip disc) for use elsewhere.
Data output
These data may be exported from ArcGIS in a choice of bitmapped formats (also known as raster graphics) including JPG, TIFF, GIF, and BMP or in a choice of vector graphics formats including Adobe Illustrator (AI), Encapsulated Postscript (EPS), and Scalable Vector Graphics (SVG). Yet another option is PDF.
Use restrictions/licensing/copyright
These data are provided for personal use for academic, research, and/or teaching purposes. Library staff will ask patrons to read and sign a data release agreement before these licensed data can be released. The Ministry of Natural Resources must be acknowledged on any derivative product, whether printed or electronic, including for example, a printed map, a raster or vector graphic, a web-based application, etc. Patrons are advised to fully respect the provisions of Canada's Copyright Act as well as terms and conditions imposed by the data provider.
Citation
NRVIS Provincial Digital Elevation Model (DEM) data. [computer file]. Toronto, Ontario: The Ontario Ministry of Natural Resources, [2002].
Sample views of data
Please click on the links below for sample views of the various surfaces and contour ouputs that are possible using a DEM file.
Triangulated Irregular Network (TIN)
TIN model allows a network of points to be joined in such a way that sloped surfaces are represented. TIN datasets contain irregularly spaced points that have x, y coordinates describing their location and a z-value that describes the surface at that particular point. TINs require 3D Analyst/ArcScene to be displayed in 3D. Please refer to page 10 of the Geospatial Centre's DEM guide (PDF) for assistance in viewing the TIN in 3D. A sample output (JPG) has been created to display a triangulated irregular network (TIN).
GRID
Grids are raster data where the underlying data model is rows and columns of cells which contain a data value. A sample output has been created to display a grid (JPG).
3D terrain model
3D Terrain modelling allows one to visualize and analyze surface data. Using ArcGIS 3D Analyst or ArcScene, you can view a surface from multiple viewpoints, create a realistic perspective image that drapes raster and vector data over a surface as well as perform three-dimensional navigation. A sample output has been created to display the 3D Terrain Model (JPG).
Hillshade model
Much of the visual effectiveness of 3D-GIS depends upon the technique of analytical hillshading. Analytical hillshading is the process of generating realistic highlights and shadows to show the visual relief of the terrain. These shading patterns help the human eye discern both elevation and form. For visualizing elevation information this approach is much more effective than hatching, and especially for the untrained eye, also superior to contour lines. A sample output has been created to display the Hillshade Model (JPG).
Contour lines
Contour lines can be generated using DEM GRIDs and TINs. You can specify the contour interval to use and then export the generated contour data to a vector export format, such as shapefile. Sample data outputs have been created for 10 metre (JPG) and 100 metre (JPG) contour lines.