National Geographic Database (NGD)
Part A - Short definition:
Part B - Detailed definition:
The National Geographic Database (NGD) is a shared database between Statistics Canada and Elections Canada. The database contains roads, road names and address ranges. It also includes separate reference layers containing physical and cultural features, such as hydrography and hydrographic names, railroads and power transmission lines.
The National Geographic Database (NGD) was created in 1997 as a joint Statistics Canada/Elections Canada initiative to develop and maintain a national road network file serving the needs of both organizations. The active building of the NGD (that is, integrating the files from Statistics Canada, Elections Canada and Natural Resources Canada) occurred from 1998 to 2000. Thereafter, Statistics Canada and Elections Canada reconciled their digital boundary holdings to the new database's road network geometry so that operational products could be derived.
Since 2001, the focus of the NGD has been on intensive data quality improvements, especially regarding the quality and currency of its road network coverage. There has been considerable expansion of road names and civic addresses ranges, as well as the addition of hydrographic names.
Since 2009, the NGD has converged its data holdings to provincially-sourced data in all of British Columbia and six census divisions in Ontario, specifically Halton, Hamilton, Ottawa, Peel, Toronto and Waterloo.
Priorities for road network file maintenance are determined by Statistics Canada and Elections Canada, enabling the NGD to meet the joint operational needs of both agencies in support of census and electoral activities.
The main sources for the NGD include:
- Statistics Canada's street network files
- Elections Canada's road network file
- National Topographic Database (NTDB) digital coverage at 1:50,000 and 1:250,000 from Natural Resources Canada, and Digital Chart of the World (DCW) coverage at 1:1,000,000
- provincially-sourced data sets
- other information from field operation activities, municipal maps and private sector licenced holdings.
The reference layers are not edge-matched at former NTDB tile limits.
Since the primary purpose of NGD is to support census and electoral activities, topological accuracy takes precedence over absolute positional accuracy.
The data are maintained and stored in the Lambert conformal conic projection based on the North American Datum of 1983 (NAD83).
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