CGRG Bibliography of Canadian Geomorphology
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Author : Bajc, A.F.; Dodge, J.; and Gao, G.
Date : 2006.
Title : A seamless surficial geology map of southern Ontario.
Publication : Joint Annual Meeting of the Geological Association of Canada and the Mineralogical Association of Canada. University of Quebec in Montreal (UQAM) May 14-17, 2006.
Issue :
Page(s) :
Abstract
In response to the demand for readily accessible and easily understood information on the surficial sediments of southern Ontario, the Ontario Geological Survey (OGS) has generated a GIS-based, seamless map of Quaternary geology for this region. Over the past 40 years, the OGS and Geological Survey of Canada (GSC) have completed Quaternary mapping, primarily at a scale of 1:50 000, for most of southern Ontario. A total of 124 maps (88 OGS and 36 GSC) were used to create the seamless coverage. These original, tiled maps existed in either digital vector or raster format. The raster images were rubber sheeted to a geographic base and digitized (heads up) according to standards established for the project. Coverages created include geology polygons, point information, line information, hummocky topography and moraines, miscellaneous areas such as dunes, pits and quarries and geological annotation. Attribute tables were built and populated with various geological related information. The original maps contained legends of varying detail and terminology; therefore, a single, standard legend suitable for a 1:50 000 compilation was constructed. This legend, created using Microsoft® Access® software, was used to translate all original map units to the new standard legend. Each of the map attribute tables was joined to the translation table using a unique key. A series of additional attributes, for instance, primary material and genesis were extracted from each map sheet and included in this table. By capturing these attributes, a variety of derivative maps can be produced. For instance, for aggregate resource assessment studies a map of gravel and sand resources can be derived from the primary material attribute. Once all attribute tables were standardized and the translation table completed, coverages were appended together to create a tiled coverage for all of southern Ontario. Misaligned contacts (boundary faults) were found to exist between individual map tiles for most polygons that cross map boundaries. These discrepancies were corrected through field investigations, examination of other geoscience data sets and utilization of a digital elevation model. At present, the map is seamless on 4 attributes: geology, primary material, genesis and formation. Coverages are available on a series of CDs and distribution on the internet is being planned.
Bibliography of Canadian Geomorphology