Identification_Information: Citation: Citation_Information: Originator: EOEA - MassGIS Publication_Date: 20050228 Title: Shaded Relief (1:5,000) Geospatial_Data_Presentation_Form: raster digital data Online_Linkage: http://wsgw.mass.gov/data/gispub/images/elevation/shdrel5k/shdrel5k.zip Description: Abstract: This raster layer, useful for cartographic display, represents a shaded relief or "hillshade" for the surface terrain of Massachusetts. Its source data were the digital terrain models that were produced as part of the 1:5,000 Black and White Digital Orthophoto imagery project. Cellsize is 10 meters by 10 meters. Each cell has a grayscale value ranging from 1 to 255. MassGIS stores the statewide image in its Oracle-based ArcSDE geodatabase as IMG_SHDREL5K. Purpose: Cartographic display Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20050228 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -73.545863 East_Bounding_Coordinate: -69.870162 North_Bounding_Coordinate: 42.909573 South_Bounding_Coordinate: 41.197561 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: hillshade Theme_Keyword: shaded relief Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: EOEA - MassGIS Contact_Person: Michael Trust Contact_Position: Sr. Database Administrator Contact_Address: Address_Type: mailing address Address: 251 Causeway Street Address: Suite 500 City: Boston State_or_Province: MA Postal_Code: 02114 Country: USA Contact_Voice_Telephone: (617) 626-1000 Contact_Facsimile_Telephone: (617) 626-1249 Contact_Electronic_Mail_Address: michael.trust@state.ma.us Hours_of_Service: 9 AM - 5 PM Native_Data_Set_Environment: Microsoft Windows Vista Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.1850 Data_Quality_Information: Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The source digital terrain model data were collected on analytical stereoplotters at a sufficient density to support generation of 3-meter contours conforming to the National Map Accuracy Standards (+ or - 1.5 meters) at the nominal scale of 1:5,000. Lineage: Source_Information: Source_Scale_Denominator: 1:5,000 Source_Contribution: Using ESRI's ArcInfo Workstation software, MassGIS ran the TOPOGRID command, using the existing 3-Meter Elevation Contours (1:5,000) layer as input. Working on an Orthophoto Quad Index tile-by-tile basis (clipping the contours out of SDE with a bit of overlap on all sides of the tile), TOPOGRID produced elevation grids based on the contours. The HILLSHADE command then produced the shaded relief grid from the output of TOPOGRID. The hillshade grids were produced with an azimuth of 315 degrees, an altitude of 45 degrees, a Z factor of 1.5, and without the effects of local shadows. To produce a continuous coastline, the outermost breaklines from the Topographic Breaklines layer were appended and edited into polygon coverages, converted to grids, and used the in the SELECTMASK () Grid function. This process allowed all off-shore areas to be coded as NODATA. For some tiles along the coast, there were too few contours to use TOPOGRID. For these, an OQ tile-based area was clipped out of the Digital Elevation Model (1:5,000) and HILLSHADE was run on that. Once grids for all tiles were completed, they were merged into one statewide grid. At this point, any grayscale values of 255 (pure white) within the land portion of the image were changed to 254 and all NODATA was converted to 255 so that when the grid was converted to a tiff image (needed for production of a MrSID image version of the layer), the only 255s would be offshore or in adjacent states, allowing for a white background around valid hillshade data. The grid version was loaded into SDE, after which pyramids were built and statistics generated. After some experimentation, the TOPOGRID-HILLSHADE approach was chosen over other methods (such as the Surface Analysis > Hillshade tool in ArcGIS' Spatial Analysis extension) because the HILLSHADE command produced the smoothest, most realistic and cartographically pleasing shaded relief image when generated from the already generalized contours, with minimal banding or other visually disturbing artifacts. In a few areas, some banding may be noticeable at large scales, a result of the irregular pattern of original sampling points in the source DTM files. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: G-polygon Point_and_Vector_Object_Count: 44 Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 18821 Column_Count: 30022 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Lambert Conformal Conic Lambert_Conformal_Conic: Standard_Parallel: 42.683333 Standard_Parallel: 41.716667 Longitude_of_Central_Meridian: -71.500000 Latitude_of_Projection_Origin: 41.000000 False_Easting: 200000.000000 False_Northing: 750000.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 10.000000 Ordinate_Resolution: 10.000000 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 1 Altitude_Distance_Units: meters Altitude_Encoding_Method: Implicit coordinate Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: shdrel5k.sid.vat Attribute: Attribute_Label: OID 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: Value Attribute: Attribute_Label: Count Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: EOEA - MassGIS Contact_Person: Michael Trust Contact_Position: Sr. Database Administrator Contact_Address: Address_Type: mailing address Address: 251 Causeway Street Address: Suite 500 City: Boston State_or_Province: MA Postal_Code: 02114 Country: USA Contact_Voice_Telephone: (617) 626-1000 Contact_Facsimile_Telephone: (617) 626-1249 Contact_Electronic_Mail_Address: michael.trust@state.ma.us Hours_of_Service: 9 AM - 5 PM Resource_Description: Data may be ordered in MrSID image format Distribution_Liability: Please see the "PURCHASE AGREEMENT FOR DIGITAL DATA PROVIDED BY THE MASSACHUSETTS EXECUTIVE OFFICE OF ENVIRONMENTAL AFFAIRS", online at http://www.mass.gov/mgis/puragree.htm. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 64.095 Ordering_Instructions: Order CD-ROM from http://www.mass.gov/mgis/order.htm Custom_Order_Process: Order CD-ROM from http://www.mass.gov/mgis/order.htm Technical_Prerequisites: MassGIS' data may be used in many standard GIS software products. See each software's vendor for technical prerequisites. Metadata_Reference_Information: Metadata_Date: 20150806 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: EOEA - MassGIS Contact_Person: Michael Trust Contact_Position: Sr. Database Administrator Contact_Address: Address_Type: mailing address Address: 251 Causeway Street Address: Suite 500 City: Boston State_or_Province: MA Postal_Code: 02114 Country: USA Contact_Voice_Telephone: (617) 626-1000 Contact_Facsimile_Telephone: (617) 626-1249 Contact_Electronic_Mail_Address: michael.trust@state.ma.us Hours_of_Service: 9 AM - 5 PM Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time