@proceedings {276,
	title = {Converting paper geologic maps to digital products; the search for an effective method},
	volume = {35},
	year = {2003},
	note = {Accession Number: 2006-037984; Conference Name: Geological Society of America, 2003 annual meeting; Seattle, WA, United States; Conference Date: 20031102; Language: English; Coden: GAAPBC; Collation: 1; Collation: 276; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200611; Monograph Title: Geological Society of America, 2003 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic},
	month = {2003/11/01/},
	pages = {276 - 276},
	publisher = {Geological Society of America (GSA) : Boulder, CO, United States},
	address = {United States},
	abstract = {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.},
	keywords = {$\#$StaffPubs, cartography, data bases, data processing, digital cartography, digital data, geographic information systems, geomorphology, Geomorphology 23, government agencies, information systems, mapping, massachusetts, National Geologic Map Database, NGMDB, survey organizations, United States},
	isbn = {00167592},
	url = {https://gsa.confex.com/gsa/2003AM/finalprogram/abstract_64322.htm},
	author = {Stephen B Mabee and Newton, R. and Stepanov, A. and Ene, D. and Ivanov, D.}
}
@techreport {367,
	title = {Geomorphology of New England},
	number = {1208},
	year = {1982},
	month = {1982},
	pages = {18},
	institution = {U.S. Geological Survey},
	address = {Reston, VA},
	abstract = {<p><span style="color: rgb(51, 51, 51); font-family: Verdana; font-size: 14px; background-color: rgb(255, 255, 255);">Widely scattered terrestrial deposits of Cretaceous or Tertiary age and extensive nearshore and fluvial Coastal Plain deposits now largely beneath the sea indicate that the New England region has been above sea level during and since the Late Cretaceous. Estimates of rates of erosion based on sediment load in rivers and on volume of sediments in the Coastal Plain suggest that if the New England highlands had not been uplifted in the Miocene, the area would now be largely a lowland. If the estimated rates of erosion and uplift are of the right order of magnitude, then it is extremely unlikely that any part of the present landscape dates back before Miocene time. The only exception would be lowlands eroded in the early Mesozoic, later buried beneath Mesozoic and Cenozoic deposits, and exhumed by stream and glacial erosion during the later Cenozoic. Many of the rocks in the New England highlands are similar to those that underlie the Piedmont province in the central and southern Appalachians, where the relief over large areas is much less than in the highlands of New England. These comparisons suggest that the New England highlands have been upwarped in late Cenozoic time. The uplift took place in the Miocene and may have continued into the Quaternary. The New England landscape is primarily controlled by the underlying bedrock. Erosion and deposition during the Quaternary, related in large part to glaciation, have produced only minor changes in drainage and in topography. Shale and graywacke of Ordovician, Cambrian, and Proterozoic age forming the Taconic highlands, and akalic plutonic rocks of Mesozoic age are all highland makers. Sandstone and shale of Jurassic and Triassic age, similar rocks of Carboniferous age, and dolomite, limestone, and shale of Ordovician and Cambrian age commonly underlie lowlands. High-grade metapelites are more resistant than similar schists of low metamorphic grade and form the highest mountains in New England. Feldspathic rocks tend to form lowlands. Alkalic plutonic rocks of Mesozoic age underlie a large area in the White Mountains of New Hampshire and doubtless are a factor in their location and relief. Where the major streams flow across the regional structure of the bedrock, the location of the crossings probably is related to some other characteristic of the bedrock, such as joints or cross faults. The course of the Connecticut River is the result of the adjustment of the drainage to the bedrock geology during a long period of time. There is no ready explanation why many of the large rivers do not cross areas of calcalkalic plutonic rock, but rather take a longer course around such areas, which tend to include segments of the divide between the streams. The presence of coarse clastic materials in Miocene rocks of the emerged Coastal Plain of the Middle Atlantic States suggests uplift of the adjacent Piedmont and of the Adirondack Mountains at that time. The Miocene rocks of the submerged Coastal Plain in the Gulf of Maine and south of New England are fine grained and contain only small amounts of fluvial gravel. Perhaps the coarse clastic materials shed by the New England highlands in late Cenozoic time are buried by or incorporated in the Pleistocene glacial deposits.</span></p>},
	keywords = {$\#$Bibliography, $\#$LegacyPublications, coastal plain, Cretaceous, Eocene, geomorphology, landscape, Miocene, New England, physiography, plateau, Pleistocene, provinces, river valleys, rivers, shallow bedrock, uplands},
	url = {https://pubs.er.usgs.gov/publication/pp1208},
	author = {C.S. Denny}
}
