Georeferencing of linear features in the compilation was done in one of three ways, depending on their origin. 1) Lineaments from figures derived from the Geological Atlas of the Western Canada Sedimentary Basin are archived by AGS as digital polylines in ASCII format contain the coordinates (i.e., latitude and longitude) of each vertex along the feature polylines. These were reassembled into georeferenced, ArcInfo coverage format of known projection and datum, using the Arc TRANSFORM command.

2) Other Geological Atlas figures are archived by AGS as Windows metafiles (*.wmf) as digital graphic files (vector format) that contain registration (fiducial) marks such as latitude-longitude graticules, township grids, etc., but are not georeferenced (i.e., they were created in a graphics software package using page coordinates, not map coordinates). The map projection of each figure was determined by trial and error. Once the projection parameters were determined, the files were transformed from page coordinates to map coordinates (using the Arc TRANSFORM command), and then converted to one common projection (ten-degree Transverse Mercator projection).

3) Paper maps from journal articles (i.e., non-digital), containing small-scale or complex features, were scanned, digitized in a graphics package, and then processed the same way as figures of Type 2. Relatively simple, large-scale features were sketched in against, for example, a digital township grid where adequate georeferencing information was shown on the figure.

Attribute information for each line feature, including unique identifier, reference, author's criteria for inferring a fault's existence (primary and secondary), formation(s) affected, fault type, dip direction of fault plane (where applicable/known) and AGS comments, were compiled into a Microsoft Access database. Information queried from the database was joined to the spatial features in ArcView and written out in ESRI shapefile format.

We made numerous corrections and refinements to the entire dataset, including:

1. Adding the source publication scale to the shapefile’s attribute table, as ‘PubScale’.

2. Renaming the field ‘Up_Down’ to ‘HW_VOffset’ (hanging wall vertical offset), and modifying its values for clarity.

3. Correcting sentences previously truncated at 255 characters (a limitation of the shapefile attribute table field length).

4. The Comments field contains citations to literature sources not directly used in this compilation (i.e., no line features were digitized from them). We added full references for these to the dataset’s metadata under Data Quality, Lineage.

5. Deleting a set of unpublished features (Abercrombie, 1999).

6. Correcting spelling errors.