This is an online version of the out-of-print Geological Atlas of the Western Canada Sedimentary Basin, as well as digital data and shapefiles for some of the content. Please see our publications FAQ regarding the contours and map projections. You may also use our suggested citation format to cite the online version.
Where are the contours for the GIS data of the Geological Atlas of the Western Canada Sedimentary Basin? We decided not to re-edit and publish these elements of the Geological Atlas of the Western Canada Sedimentary Basin. Instead we chose to publish the grid data on which the contours were based because we thought these would be more flexible for people. The reasoning was that any surface software package or GIS can generate contours for a given grid, at whatever interval the user needs. You can download the grids
What are the map projections for the maps of the Geological Atlas of the Western Canada Sedimentary Basin? Most of the maps in the Geological Atlas of the Western Canada Sedimentary Basin were plotted using an in-house cartographic program. These maps have custom projection parameters depending upon the geographic extent of the area shown. All are in Lambert conformal conic projection.
Three of the standard Lambert-projection parameters were determined on-the-fly: the central meridian and the first and second standard parallels. You can back-calculate these three values by examining their geographic extents and by using the below equations.
The central meridian is the line of longitude that is vertical on the page (i.e., it's exactly in the middle of the page).
The first standard parallel (or southern line of latitude) is the latitude 25% north of the southernmost latitude of the map.
The second standard parallel is the latitude 25% south of the northernmost latitude of the map.
For example, the map on Figure 5.12 spans from 96° west longitude on the east side of the map to 126° west longitude on the west side. Therefore, the central meridian is halfway between: 111° west longitude.
The map extends from 45° to 64° in a north-south direction. Therefore, the first standard parallel is at 49.75° north latitude.
45° + (64°-45°)/4 = 49.75°
The second standard parallel is at 59.25° north latitude.
64° - (64°-45°)/4 = 59.25°
The latitude of origin for all atlas maps is 0°.
Citation for the entire publication:
Mossop, G.D. and Shetsen, I., comp. (1994): Geological atlas of the Western Canada Sedimentary Basin; Canadian Society of Petroleum Geologists and Alberta Research Council, URL <https://ags.aer.ca/reports/atlas-western-canada-sedimentary-basin>, [Date last accessed online].
Citation for specific chapters, reference the corresponding author. Example:
O'Connell, S.C. (1994): Geological history of the Peace River Arch; in Geological Atlas of the Western Canada Sedimentary Basin, G.D. Mossop and I. Shetsen (comp.), Canadian Society of Petroleum Geologists and Alberta Research Council, URL https://ags.aer.ca/atlas-the-western-canada-sedimentary-basin/chapter-28-geological-history-the-peace-river-arch , [Date last accessed online].