Shaded Relief (1:5,000)

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

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://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/datalayers/imgshdrel5k.html

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

Browse_Graphic:

Browse_Graphic_File_Type: PNG

Native_Data_Set_Environment:

Microsoft Windows Vista Version 6.1 (Build 7601) Service Pack 1; ESRI ArcCatalog 9.3.1.4095

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.

Process_Step:

Process_Description: Metadata imported.

Source_Used_Citation_Abbreviation: C:\temp\img_shdrel5k.xml

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: 20140314

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