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The Locality Table within the database stores all of the spatial and temporal location information (at least in the earliest versions of the database). Space and time are of critical importance in geology. If you don't know when and/or where a specimen or section was from then it is pretty much useless for futher scientific analysis. All of the data in the database is tied to modern latitude and longitude, locations that can then rotated to their palaeo positions. A considerable amount of time was spent checking the location of localities, which has proved invaluable now that all of this data has been placed within a GIS environment. Because not all locations represent a single point in space, or not precisely located, the database includes qualifiers reflecting the precision (grain) with which a particular locality is placed.
As of 1995, when I stopped compiling data for my thesis, the database contained information on almost 6000 individual vertebrate localities.
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LEFT: A screen image (click on the the thumbnail to get a larger image, 104kb) of the Locality entry form (top half).
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The position of a locality in time is as important as it's spatial location, and again this had to be rigorously constrained. The database records the basis of an age assignment (e.g. biostratigraphic, radiometric, etc.) and the range of time represented. For most localities this is a chronostratigraphic age. This is converted to an absolute age through a lookup table that contains the absolute age assignment for the top and bottom of the recorded stratigraphic interval based on a chosen published timescale (a number of different timescales are included in the database). However, this raised issues as to what was actually meant by a 'locality' since multiple entries in this part of the database could simply represent different depths at the same spatial location (e.g. a well, or road section). As a consequence the database was redesigned to include a separate spatial definition and depth fields were included in the "Locality" table.
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LEFT: A screen image (click on the the thumbnail to get a larger image, 84kb) of the Locality entry form (bottom half). |
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The database is also used to store lithological information for each locality and in many cases this may be a quite detailed desciption of a whole section.
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