Digital version of the Cape Cod and the Islands Geologic Map (CAPE_GEOLGEOG shapefile, Geographic, NAD83)

The original paper map was scanned and converted to a TIFF image using a large format scanner in Reston, VA.

This original TIFF image was then registered using BlueMarble geographic transformer software. This original georeferencing was based on the UTM, zone 19, NAD27 tic marks available on the map.

This UTM, Zone 19, NAD27 image was then reprojected using BlueMarble geographic transformer to UTM, Zone 19, NAD83.

Using this UTM, NAD83 image as a backdrop, the geologic contacts were heads up digitized in ESRI's ArcMap, 8.2 software.

Attributes reflecting the information recorded on the original geologic map were added to the shapefile.

Within ArcView 3.2, the avenue script calcapl.ave was run on the shapefile to help identify sliver polygons.

Due to the large number of sliver polygons, the decision was made to convert the shapefile to a coverage using the ArcInfo command shapearc. A subclass was specified so that the attribute information already in the shapefile would be carried over to the coverage.

Once the shapefile was in a coverage, CLEAN was run on the coverage with a fuzzy tolerance of 1 and a dangle tolerance of 0.

This polygon coverage was then converted back to a shapefile with unnecessary attribute columns deleted.

Polygons with small areas were looked at more closely to see if any larger sliver polygons escaped the clean process. Those that did escape were merged with the adjacent larger polygons of the same geologic unit.

Once the shapefile was cleaned and edits were complete, the UTM projected shapefile was projected to geographic coordinates.

Edits to the metadata were made to fix any errors that MP v 2.9.30 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. None of the original process steps had process dates, so the value of unknown was used. Other minor edits were probably performed (title, publisher, publication place, etc.). The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Added keywords section with USGS persistent identifier as theme keyword.