FAQ: What are some common projections and geographic coordinate systems for Canada?
What are some common projections and geographic coordinate systems for Canada?
This article was contributed by Esri Canada.
The projections and geographic coordinate systems (GCS) used to define data in ArcGIS are an important part of working with GIS data. Below is an overview of some of the most common projections and geographic coordinate systems for Canada.
Geographic coordinate system: A reference system that uses latitude and longitude to define the locations of points on the surface of a sphere or spheroid. A geographic coordinate system definition includes a datum, prime meridian, and angular unit.
Commonly used geographic coordinate systems in Canada:
· North American Datum 1927 (NAD 1927)
· NAD 1927- CGQ77
· NAD 1927 definition 1976 for Ontario
· North American Datum 1983 (NAD 1983)
· NAD 1983 - CSRS98 (Canadian Spatial Reference System)
· Average Terrestrial System of 1977 (ATS77)
Projected coordinate system: A projected coordinate system is defined by a geographic coordinate system, a map projection, any parameters needed by the map projection and a linear unit of measure. Every map projection distorts distance, area, shape, direction, or some combination thereof.
Commonly used projected coordinate systems in Canada:
· Universal Transverse Mercator (UTM)
· Modified Transverse Mercator (MTM)
· 10 degree Transverse Mercator (10TM)
· 3 degree Transverse Mercator (3 TM)
· Albers Equal Area Conic
· Lambert Conformal Conic
For more information about the terms geoid, ellipsoid, spheroid, and datum, and how they are related, refer to the article: What do the terms geoid, ellipsoid, spheroid and datum mean, and how are they related?
- FAQ: Projection Basics: What the GIS professional needs to know
- HowTo: Select a suitable map projection or coordinate system