%0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2003 %T Converting paper geologic maps to digital products; the search for an effective method %A Stephen B Mabee %A Newton, R. %A Stepanov, A. %A Ene, D. %A Ivanov, D. %K #StaffPubs %K cartography %K data bases %K data processing %K digital cartography %K digital data %K geographic information systems %K geomorphology %K Geomorphology 23 %K government agencies %K information systems %K mapping %K massachusetts %K National Geologic Map Database %K NGMDB %K survey organizations %K United States %X MassGIS and the Office of the Massachusetts State Geologist are working collaboratively with the USGS to vectorize 85, published 7.5-minute surficial geologic maps in order to prepare a statewide coverage of the till-glacial stratified drift boundary. Conversion of old geologic maps from paper copies to new digital products is a complex task requiring an efficient method that minimizes errors and limits the need for heads-up digitizing. The main issue in the conversion is the accurate separation of line work (geologic contacts) on the map from the halftone colors in the polygon fills and achieving this without creating an extensive editing effort in the GIS environment. For this project, we elected to process the scanned and rectified images of the surficial geologic maps in Photoshop and adjust the resulting line work in ArcScan before vectorizing the polygons. Photoshop is an extremely sophisticated, commercial raster image editing software with a very user-friendly interface. Using tools such as the "Magic Wand" (selection of similar pixels with variable threshold control), "Select Color Range" (find all instances of similar colors), "Grow and Contract Selection", "Stroke Selection", and Photoshop "Layers", we are able to create a set of very accurate, noise free boundary lines, before the vectorization process occurs. This methodology is, in effect, "on the fly" editing of the boundary lines, eliminating the large number of errors and artifacts that "automated" vectorizing processes inevitably generate (and which must be tediously edited and/or removed later with vector editing software). Line tracings produced in Photoshop are exported to ArcScan where, using the original raster image as a background, a preview of the proposed vector is adjusted, if needed, using simple editing tools in ArcScan. Once an optimal match is achieved visually, the vectors are generated. The advantage of this approach is that the bulk of the line editing occurs early in the process, prior to vectorization, and can be achieved by moderately trained personnel using "off the shelf" commercial software. This provides greater control of the quality of the finished product because there are no computer generated false lines that need to be found and removed later with a much more complex process. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 35 %P 276 - 276 %8 2003/11/01/ %@ 00167592 %G eng %U https://gsa.confex.com/gsa/2003AM/finalprogram/abstract_64322.htm %N 66 %! Abstracts with Programs - Geological Society of America %0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2000 %T Geochemistry of gneisses and amphibolites in the Uchee Belt of western Georgia and eastern Alabama; an ACRES progress report %A Joseph P Kopera %A Nicholas, Brian %A Todd, Dave %A Davison, Jeff %A Hanley, Tom %A Kar, Aditya %A La Tour, Timothy E. %A Edwards, Tonya %K #StaffPubs %K Alabama %K amphibolite %K chemical composition %K Columbus Georgia %K dikes %K Georgia %K gneisses %K Igneous and metamorphic petrology 05A %K inclusions %K intrusions %K metamorphic rocks %K Muscogee County Georgia %K Uchee Belt %K United States %K xenoliths %X Undergraduate students, high school teachers, and university faculty representing ACRES (Atlanta Consortium for Research in Earth Sciences) studied lineated gneiss (LG) exposed at Flat Rock Park (FRP) and vicinity in Columbus, GA, and Motts gneiss (MG) in eastern Alabama. The LG and MG are mineralogically and geochemically granitoidal lineated orthogneisses. They contain deformed mafic xenoliths, as well as aplitic, granitic and pegmatoidal dikes that cut the dominant lineation. Based on chemical analyses, the LG from FRP and the MG plot as granite on the IUGS diagrams and the Le Bas diagram. Similarity in incompatible trace element ratios (e.g., Zr/Nb) and highly evolved characteristics of aplite with respect to the host gneisses, indicate there is probably a genetic link between the MG and the FRP LG. These rocks are chemically distinct from other nearby felsic gneiss. Phenix City gneiss amphibolites from Lindsey Creek and North Highland Mills dam in Columbus were also analyzed for major and trace elements. These amphibolites are low K tholeiitic rocks with an island arc affinity and are similar to rocks from the area that have already been analyzed. The amphibolites show a wide range of fractionation (41 to 62 percent SiO (sub 2) ). Consistency in incompatible element ratios over a wide range of fractionation of some of the samples show a probable genetic relationship among the various amphibolites of Lindsey Creek. Future work should involve more extensive collecting and analysis of both felsic rocks and amphibolites in the Uchee belt. More time should also be spent describing the thin sections of the existing collection and comparing the REE patterns for the FRP, MG and other felsic rocks in the Uchee belt. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 32 %P 31 - 31 %8 2000/03/01/ %@ 00167592 %G eng %N 22 %! Abstracts with Programs - Geological Society of America