Entity_and_Attribute_Information:
  Detailed_Description:
    Entity_Type:
      Entity_Type_Label: geology_detailed
    Attribute:
      Attribute_Label: OBJECTID
      Attribute_Definition: Internal feature number.
      Attribute_Definition_Source: Esri
      Attribute_Domain_Values:
        Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated.
    Attribute:
      Attribute_Label: Shape
      Attribute_Definition: Feature geometry.
      Attribute_Definition_Source: Esri
      Attribute_Domain_Values:
        Unrepresentable_Domain: Coordinates defining the features.
    Attribute:
      Attribute_Label: Code
    Attribute:
      Attribute_Label: MapUnit
    Attribute:
      Attribute_Label: Formation
    Attribute:
      Attribute_Label: Epoch
    Attribute:
      Attribute_Label: Area_acres
    Attribute:
      Attribute_Label: Area_ha
    Attribute:
      Attribute_Label: Area_m2
    Attribute:
      Attribute_Label: Perimtr_m
    Attribute:
      Attribute_Label: Perimtr_mi
    Attribute:
      Attribute_Label: Shape_Length
      Attribute_Definition: Length of feature in internal units.
      Attribute_Definition_Source: Esri
      Attribute_Domain_Values:
        Unrepresentable_Domain: Positive real numbers that are automatically generated.
    Attribute:
      Attribute_Label: Shape_Area
      Attribute_Definition: Area of feature in internal units squared.
      Attribute_Definition_Source: Esri
      Attribute_Domain_Values:
        Unrepresentable_Domain: Positive real numbers that are automatically generated.
Identification_Information:
  Description:
    Abstract: This dataset contains the geologic map units of the island of Guam.
    Purpose: This dataset was developed to provide up-to-date GIS coverage of geologic information that reflects the recent update of the Geologic Map of Guam (2008) by Siegrist and Reagan. The map was originally published in 2008 as a 1:50,000-scale hard-copy map and in digital format as PDFs consisting of nine 1:24,000-scale and one 1:50,000-scale. Reference: Siegrist, H.G. and Reagan, M.K.. Geologic Map and Sections of Guam, Mariana Islands (1:50,000), Revisions of original map from USGS Professional Report 403A, 1964, by Tracey, J.I., Jr., Schlanger, S.O., Stark, J.T., Doan, D.B. & May, H.G.
  Data_Set_Credit:
    Siegrist, H.G., and Reagan, M.K. 2008. Geologic Map and Sections of Guam, Mariana Islands (1:50,000), Revisions of original map from USGS Professional Report 403A, 1964, by Tracey, J.I., Jr., Schlanger, S.O., Stark, J.T., Doan, D.B. & May, H.G. 

    Additional contributions to the map in form of field interpretations were made by Richard H. Randall and John W. Jenson. Digital cartography in Adobe Illustrator by Linda Masonic (USGS). Geographic Information System (GIS) database by Maria Kottermair, University of Guam (WERI).
  Point_of_Contact:
    Contact_Information:
      Contact_Position: Professor of Environmental Geology
      Contact_Address:
        Address_Type: mailing and physical address
        Address: University Drive
        City: Mangilao
        State_or_Province: Guam
        Postal_Code: 92923
        Country: U.S.A.
      Contact_Electronic_Mail_Address: jjenson@uguam.uog.edu
      Contact_Voice_Telephone: 671-735-2689
      Contact_Organization_Primary:
        Contact_Organization: Water & Environmental Research Institute (WERI), University of Guam
        Contact_Person: Dr. John Jenson
  Citation:
    Citation_Information:
      Originator: Water & Environmental Research Institute, University of Guam
      Publication_Date: 2012
      Title: Guam Geologic Map Units
      Online_Linkage: www.hydroguam.net
      Geospatial_Data_Presentation_Form: vector digital data
  Keywords:
    Theme:
      Theme_Keyword: Geologic Map of Guam
      Theme_Keyword: geologic features
      Theme_Keyword: map units
      Theme_Keyword: geology
    Place:
      Place_Keyword: Guam
      Place_Keyword: Mariana Islands
      Place_Keyword: Pacific Islands
      Place_Keyword: Western Pacific
      Place_Keyword: Northwestern Pacific
      Place_Keyword: United States Possesion
  Time_Period_of_Content:
    Time_Period_Information:
      Single_Date/Time:
        Calendar_Date: 2008
    Currentness_Reference: publication date
  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: As needed
  Use_Constraints: Dataset is for planning purpose only, not for use in litigation. The Water & Environmental Research Institute (WERI) cannot assume liability for any damages or misrepresentations caused by any inaccuracies in the data or as a result of the data to be in a particular system.
Data_Quality_Information:
  Logical_Consistency_Report: The logical consistency of the geometry of this dataset was checked using the ET GeoWizard tool "Clean Polygon Layer" and "Clean gaps".
  Lineage:
    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: H.G. Siegrist, Jr and Mark K. Reagan
          Publication_Date: 2008
          Title: Geologic Map of Guam
          Other_Citation_Details: Siegrist, H.G., and Reagan, M.K. 2008. Geologic Map and Sections of Guam, Mariana Islands (1:50,000), Revisions of original map from USGS Professional Report 403A, 1964, by Tracey, J.I., Jr., Schlanger, S.O., Stark, J.T., Doan, D.B. & May, H.G.
          Online_Linkage: http://www.weriguam.org/locally-sponsored-research/guam-hydrologic-survey/page/geologic-maps.html
      Type_of_Source_Media: PDF files
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Single_Date/Time:
            Calendar_Date: 2008
        Source_Currentness_Reference: publication date
      Source_Contribution: Primary source for on-screen digitizing.
    Process_Step:
      Process_Description: All nine (9) Geologic Map of Guam quadrangle maps (1:24,000) in PDF-format were exported to TIFF in Adobe Photoshop. Each map was then imported to ArcMap and georeferenced using the four corners of each map for ground control points (GCPs). The Total RSME Error for each quadrangle map was between 0.27 and 0.65 meter. A first order polynomial (affine) transformation was used to rectify the images. The 1:50,000  map covering all of Guam was also rectified using over 50 GCPs. However, it was only used as reference and not as source data since it did not overlay the USGS topographic maps (DRGs) and the WorldView2 satellite imagery as well as the quadrangle maps.
      Process_Date: 2011
      Process_Contact:
        Contact_Information:
          Contact_Person_Primary:
            Contact_Person: Maria Kottermair
            Contact_Organization: Water & Environmental Research Institute, University of Guam
          Contact_Position: Research Assistant III (GIS Analyst)
          Contact_Voice_Telephone: 671-735-2685
          Contact_Electronic_Mail_Address: mariakottermair@uguamlive.uog.edu
    Process_Step:
      Process_Description: The rectified images were then used to trace the outlines of the geologic features using ArcScan. Attributes as seen on the maps were added. The outlines were extended beyond the shoreline and later clipped using the 2006 shoreline polygon.
      Process_Date: 2011/2012
      Process_Contact:
        Contact_Information:
          Contact_Person_Primary:
            Contact_Person: Maria Kottermair
    Process_Step:
      Process_Description: Topology of the polygons was checked using the ET GeoWizard tool "Clean Polygon Layer" and "Clean gaps".
      Process_Date: 2012
      Process_Contact:
        Contact_Information:
          Contact_Person_Primary:
            Contact_Person: Maria Kottermair
      Source_Produced_Citation_Abbreviation: Guam_Geology_Update_2008
  Attribute_Accuracy:
    Attribute_Accuracy_Report: This dataset is considered complete and accurate based on the source maps. Presently, there are no plans to conduct an accuracy assessment. Updates may be provided at a later date as more ground-truthing information becomes available.
  Completeness_Report: This dataset is considered complete.
  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report: The polygons were created by tracing the nine (9) georeferenced Geologic Map of Guam quadrangle maps (1:24,000). The quadrangle topo maps follow the National Map Accuracy Standard. The geologic map is likely to follow that standard although no documentation was found to support that. Additional errors may have been introduced by geo-referencing and/ or digitizing. However, both types of errors are believed to be minor as geo-referencing was done by using the coordinates of the four corners of each map as ground control points; the georefernced maps overlaid well the USGS topo maps (< 10 meter discrepancy) and WorldView2 satellite imagery. Also, the outlines of the polygons were traced using ArcScan and should therefore be identical to the scanned georeferenced map. No positional accuracy assessment has been performed in the field.
Metadata_Reference_Information:
  Metadata_Date: 20120921
  Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
  Metadata_Contact:
    Contact_Information:
      Contact_Person_Primary:
        Contact_Person: Maria Kottermair
        Contact_Organization: Water & Environmental Research Institute, University of Guam
      Contact_Position: Research Assistant III (GIS Analyst)
      Contact_Voice_Telephone: 671735-2685
      Contact_Electronic_Mail_Address: mariakottermair@uguamlive.uog.edu
  Metadata_Review_Date: 20131010
Spatial_Reference_Information:
  Horizontal_Coordinate_System_Definition:
    Geodetic_Model:
      Horizontal_Datum_Name: D_WGS_1984
      Ellipsoid_Name: WGS_1984
    Planar:
      Planar_Coordinate_Information:
        Planar_Distance_Units: meters
Spatial_Data_Organization_Information:
  Point_and_Vector_Object_Information:
Lineage:
