A STREAMLINED METHOD OF DIGITIZING GEOLOGIC MAPS

Feature templates in ArcGIS 10 allow the digitizer to define feature symbology and default attributes once per feature type. Templates can then be saved and used with the next project, saving time and reducing coding errors. In the process of building templates for use at the New Mexico Bureau of Geology and Mineral Resources (NMBGMR), it became apparent that one could also use predefined line and point types. This was common practice in the earlier days of ARC/INFO 6.0. Look-up tables with line/point types and their associated code worked quite well, albeit with the lack of type definitions. The development of a set of definitions of all possible line and point types associated with digital geologic maps was completed and eventually manifested itself in the Federal Geographic Data Committee (FGDC) Digital Cartographic Standard for Geologic Map Symbolization. This document defines the symbology for each possible feature on the map, provides a brief description of the feature and provides a reference number or "code", which can then be used as a linking tool between symbology and feature tables. This code now provides a standard by which all digital maps must adhere, and by extension, implies that all digital geologic maps can use the same digitizing templates. The final and possibly most useful development came when the Geological Survey of Canada (GSC), Natural Resources Canada, kindly provided their interim implementation of the FGDC Digital Cartographic Standard for Geologic Map Symbolization. This implementation includes an ESRI style file and a true-type font set. Now all the necessary parts are available to employ any data model, apply the use of templates, digital cartographic standards and an accompanying style file to produce consistent digital map products again and again. The digital mapping team at the NMBGMR currently uses our in-house data model, the NMBGMR Draft Geologic Map Data Model. However, regardless of what map data model one adopts, the tools provided by ArcGIS 10 and others in the ArcGIS community now allow us to streamline and consistently replicate the geologic map digitizing process.