Summary The Canadian Digital Elevation Data (CDED) consists of an ordered array of ground elevations at regularly spaced intervals. The CDED is based on National Topographic Data Base (NTDB) digital files at scales of 1:50 000 and 1:250 000 or various scaled positional data acquired from the provinces and territories, ... according to the National Topographic System (NTS).
The coverage for every file corresponds to half an NTS map, which means that there are western and eastern parts to the CDED for each NTS map. The grid spacing is based on geographic coordinates at a maximum and minimum resolution of 0.75 and 3 arc seconds for the 1:50 000, and 3 and 12 arc seconds for the 1:250 000 respectively, depending on latitude. A CDED file consists of elevation data recorded in metres relative to Mean Sea Level (MSL) based on the North American Datum 1983 (NAD83) horizontal reference datum. The Centre for Topographic Information (CTI) jointly produces the CDED with federal, provincial and territorial government agencies as well as the private sector, using terrain-modelling software.CDED has assumed a major role in digital mapping. The data is used in Geographic Information Systems (GIS) for land-management applications. CDED plays the same role as contours and relief shading on conventional paper maps but is more powerful analytically. In addition to providing estimated values of elevation points, CDED can be used to determine orientation and the slope of each point when used in GIS applications. CDED can also be used for terrain modelling, for calculating the influence of the terrain on line-of-sight, for radar imaging, for simulating flooding and similar applications. Spatial Data Organization Information -
Indirect Spatial Reference: Direct Spatial Reference: Raster Object Type: Row Count: Column Count: Vertical Count: Spatial Reference Information - Horizontal Coordinate System Definition -
Geodetic Model: Horizontal Datum Name: North American Datum of 1983 (NAD83) Ellipsoid Name: Global Reference System of 1980 (GRS80) Semi-major Axis: 6378137 Denominator of Flattening Ratio: 298.257222101
Name:
CUSTOMERS
SUPPORT
GROUP Phone:
+1-800-661-2638 (Canada and USA)
Fax:
+01-819-564-5698
Email:
ntdb at nrcan.gc.ca
Contact Address:
2144, King St. West, Suite 010 City:
Sherbrooke
Province or State:
Quebec
Postal Code:
J1J 2E8
Country:
Canada
Personnel
DANIEL
CLAVET Role:
DIF AUTHOR
Phone:
+01-819-564-5600 extension 255
Fax:
+01-819-564-5698
Email:
daniel.clavet at nrcan.gc.ca
Contact Address:
2144 King St. West, Suite 010 City:
Sherbrooke
Province or State:
Quebec
Postal Code:
J1J 2E8
Country:
Canada
CUSTOMERS
SUPPORT
GROUP Role:
TECHNICAL CONTACT
Phone:
+1-800-661-2638 (Canada and USA)
Fax:
+01-819-564-5698
Email:
ntdb at nrcan.gc.ca
Contact Address:
2144, King St. West, Suite 010 City:
Sherbrooke
Province or State:
Quebec
Postal Code:
J1J 2E8
Country:
Canada
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