Allegheny County - Spot Elevation

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Distributor 1
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator:Allegheny County Division of Computer Services Geographic Information Systems Group

Publication_Date:2006

Title:

Allegheny County - Spot Elevation

Geospatial_Data_Presentation_Form:vector digital data

Series_Information:

Series_Name:Base Data

Publication_Information:

Publication_Place:Pittsburgh, PA

Publisher:Allegheny County Division of Computer Services Geographic Information Systems Group

Online_Linkage: https://www.pasda.psu.edu

Description:

Abstract:

Spot Elevation data was created as a result of a county flyover in the spring of 2004. They were created from a DTM Feature Dataset, upgraded by Baker and T-3 to support National Mapping Accuracy Standards (NMAS). Spot Elevations are used to show additional elevation information.  They are located in flat areas where contours may be sparse or spaced far apart, at road and railroad intersections, on the road centerline at the ends of bridges, on the road centerline over the center of culverts that have a span of five (5)-foot or greater, at the crest of all tops of hills, at saddles, within depressions and where the ground is visible in obscured areas.

Purpose:

Data was developed as part of the continuing effort to establish and maintain large scale base data in support of the Geographic Information System in Allegheny County.

Supplemental_Information:

Data meets or exceeds map accuracy standards in effect during the spring of 2004. Digital Globe and Michael Baker Corporation held a contract with Allegheny County to fly the County to produce digital orthophotography and to update planimetric base data for the approximate 730 square miles of Allegheny County.  Subcontractors for the project included: T3 Global Strategies, Sweet Solutions and Keystone Aerial Surveys.  Photography was produced at a scale of 1"=1600'. Mapping was stereo digitized at a scale of 1"=200'. Digital Orthophotos were included as a deliverable.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date:Spring 2004

Currentness_Reference:

publication date

Status:

Progress:Complete

Maintenance_and_Update_Frequency:As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate:-80.373199

East_Bounding_Coordinate:-79.671427

North_Bounding_Coordinate:40.686763

South_Bounding_Coordinate:40.181481

Keywords:

Theme:

Theme_Keyword_Thesaurus:ISO 19115 Topic Categories

Theme_Keyword:elevation

Theme_Keyword:imageryBaseMapsEarthCover

Place:

Place_Keyword:Allegheny County

Place_Keyword:Pittsburgh

Place_Keyword:Southwest Pennsylvania

Access_Constraints:Call for Details

Use_Constraints:

All parties acknowledge that the data is for informational purposes only. The existing digital data is shipped as is and there is no guarantee as to its completeness or accuracy. Allegheny County Division of Computer Services Geographic Information Systems Group is not responsible for any reliance upon said data.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:Allegheny County Division of Computer Services Geographic Information Systems

Contact_Position:GIS Manager

Contact_Address:

Address_Type:mailing and physical address

Address:

621 County Office Building

Address:

542 Forbes Ave.

City:Pittsburgh

State_or_Province:PA

Postal_Code:15219

Country:United States

Contact_Voice_Telephone:(412) 350-4774

Contact_Facsimile_Telephone:(412) 350-4754

Contact_Electronic_Mail_Address:GIShelp@alleghenycounty.us

Native_Data_Set_Environment:

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722

Cross_Reference:

Citation_Information:

Originator:Allegheny County Division of Computer Services Geographic Information Systems Group

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Spot Elevation accuracy is such that 90% of all spot elevations are accurate to within 1/4th of the contour interval and 10% will be accurate to within one contour level.

Logical_Consistency_Report:

Data was subject to QA/QC process at the time it was created. Data was created as part of the County's base layer(s) update in the spring of 2004.

Completeness_Report:

Data was created for all of Allegheny County.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

All horizontal control is to NGS Second Order Class I accuracy or better and photo control points are reported on the North American Datum (NAD) 1983 U.S. Survey Feet.  The aerial photography was captured at a negative scale of 1" = 1,600' and is sufficient to produce mapping at 1" = 200' that conforms to National Mapping Accuracy Standards (NMAS).

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value:+/- 5 feet

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

All final elevations are referenced to North American Vertical Datum (NAVD) 1988.  Orthometric heights utilize GEOID 99.  The network adheres to the Federal Geodetic Control Committee Standards (FGCS) guidelines and the final constrained adjustments were made with StarNet Least Squares Adjustment program and are acceptable by the National Geodetic Survey (NGS).

Quantitative_Vertical_Positional_Accuracy_Assessment:

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator:Allegheny County Division of Computer Services Geographic Information Systems Group

Publication_Date:2006

Title:

Base Data 2004 Flyover

Series_Information:

Series_Name:2004 Flyover

Publication_Information:

Publication_Place:Allegheny County

Publisher:Allegheny County Division of Computer Services Geographic Information Systems Group

Source_Scale_Denominator:200'

Type_of_Source_Media:CD-ROM

Source_Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date:2004

Ending_Date:2006

Source_Currentness_Reference:

publication date

Source_Contribution:

Digital Globe and Michael Baker Corporation held a contract with Allegheny County to fly the County to produce digital orthophotography and to update planimetric base data for  Allegheny County.  Subcontractors for the project included: T3 Global Strategies, Sweet Solutions and Keystone Aerial Surveys.

Process_Step:

Process_Description:

Using existing County DTM files referenced to NGVD 1929 Vertical Datum, an average countywide elevation difference between the cuerrent data and the NAVD 1988 was determined. Existing DTM was shifted the averaged amount, enabling it to be updated to meet the NMAS (National Mapping Accuracy Standards) vertical accuracy requirements for 5' contour mapping. Corresponding MicroStation graphics files in stereo model units were generated. With the use of softcopy stereo workstations, each MicroStation model file of existing data was super-imposed on the corresponding stereo imagery created during this fly-over. Break lines, mass points and breaklines were updated as needed. Breaklines were captured at all slope breaks such as ridge and valley lines, roads and railroads. All hydrographic features were captured as breaklines and used in the triangulation process to ensure contour turnbacks that fit the water features. The same rules were applied to new compilation and updates.

Process_Date:2004

Process_Step:

Process_Description:

The normal mass point density of 20-25 times the contour interval may have been adjusted depending on the type of terrain being mapped. Uneven terrain requires a denser spacing than flat or gently rolling terrain. In addition spot elevations were digitized in the DTM file at the following locations:
Road/railroad intersections
On the road centerline at the abutment and center of bridges and similar structures
On road centerlines over major culverts
At the crest of closed contours
At the lowest point of all closed depression contours, significant saddles, cuts and depressions
At the intersection point of tributaries with the center of the main channel
In areas of dense vegetation where the ground is visible

Process_Step:

Process_Description:

Following the completion of the DTM data collection, check contours were developed by the stereo operator, enabling them to be viewed with the stereo model. InRoads Software loads the features from the DTM and generates a three dimensional contour file. Spot elevations could then be added at peaks and saddles, as well as additional breaklines and mass points, if needed. When the stereo operator was satisfied with the DTM, files were provided to map editors for final contour generation and editing.

Process_Step:

Process_Description:

ArcInfo coverages were created from MicroStation design files using in-house developed translation software. Allegheny County's Data Dictionary was used as the base upon which the ArcInfo structure was designed. Each coverage was subjected to review and inspection using ArcMap. Any revisions or corrections were performed in the MicroStation design files. After any corrections were performed, the files were re-translated, re-plotted and re-checked to confirm correct translations. ArcMap was then used to visually check the planimetric data against the digital orthophoto on a tile basis. The final QC step was to merge all tiles to verify the edgematch. Validation was done using MRF. The ESRI tool LOADDATA was used to convert coverages to the final deliverable format, the geodatabase.

Source_Produced_Citation_Abbreviation:

Michael Baker Engineers

Process_Step:

Process_Description:

Data was loaded into SDE

Source_Used_Citation_Abbreviation:

County GIS Staff

Process_Time:2004-2005

Process_Step:

Process_Description:

Metadata was created

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method:Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type:Entity point

Point_and_Vector_Object_Count:99451

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type:Point

Point_and_Vector_Object_Count:1756

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type:Label point

Point_and_Vector_Object_Count:30990

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name:Lambert Conformal Conic

Lambert_Conformal_Conic:

Lambert Conformal Conic

Standard_Parallel:39.933333

Standard_Parallel:40.966667

Longitude_of_Central_Meridian:-77.750000

Latitude_of_Projection_Origin:39.333333

False_Easting:1968500.000000

False_Northing:0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method:coordinate pair

Coordinate_Representation:

Abscissa_Resolution:0.000512

Ordinate_Resolution:0.000512

Planar_Distance_Units:survey feet

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:0.000001

Altitude_Distance_Units:feet

Altitude_Encoding_Method:Explicit elevation coordinate included with horizontal coordinates

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label:spotelev

Attribute:

Attribute_Label:FID

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:ELEVATION

Attribute:

Attribute_Label:Shape

Attribute_Definition:

Feature geometry.

Attribute_Definition_Source:

ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Coordinates defining the features.

Attribute:

Attribute_Label:UPDATE_YEA

Attribute:

Attribute_Label:X_COORDINA

Attribute:

Attribute_Label:FEATURECOD

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value:1410

Enumerated_Domain_Value_Definition:

Spot Elevations

Enumerated_Domain_Value_Definition_Source:

Large Scale Database Quality Control Guide, March 1, 1993

Enumerated_Domain:

Enumerated_Domain_Value:1420

Enumerated_Domain_Value_Definition:

Water Elevations

Enumerated_Domain_Value_Definition_Source:

Large Scale Database Quality Control Guide, March 1, 1993

Attribute:

Attribute_Label:Y_COORDINA

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:Allegheny County Division of Computer Services Geographic Information Systems Group

Contact_Position:GIS Manager

Contact_Address:

Address_Type:mailing and physical address

Address:

621 County Office Building

Address:

542 Forbes Avenue

City:Pittsburgh

State_or_Province:PA

Postal_Code:15219-2952

Country:USA

Contact_Voice_Telephone:412 350-4774

Contact_Facsimile_Telephone:412 350-4754

Resource_Description:Call for details.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Transfer_Size:66.284

Ordering_Instructions:

Call for Details

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:Pennsylvania Spatial Data Access (PASDA)

Contact_Address:

Address_Type:mailing address

Address:

115 Land and Water building

City:University Park

State_or_Province:Pennsylvania

Postal_Code:16802

Country:United States

Contact_Voice_Telephone:(814) 865 - 8792

Contact_Electronic_Mail_Address:pasda@psu.edu

Distribution_Liability:

The USER shall indemnify, save harmless, and, if requested, defend those parties involved with the development and distribution of this data, their officers, agents, and employees from and against any suits, claims, or actions for injury, death, or property damage arising out of the use of or any defect in the FILES or any accompanying documentation. Those parties involved with the development and distribution excluded any and all implied warranties, including warranties or merchantability and fitness for a particular purpose and makes no warranty or representation, either express or implied, with respect to the FILES or accompanying documentation, including its quality, performance, merchantability, or fitness for a particular purpose. The FILES and documentation are provided "as is" and the USER assumes the entire risk as to its quality and performance. Those parties involved with the development and distribution of this data will not be liable for any direct, indirect, special, incidental, or consequential damages arising out of the use or inability to use the FILES or any accompanying documentation.

Metadata_Reference_Information:

Metadata_Date:20080310

Metadata_Review_Date:August, 2006

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:Allegheny County Division of Computer Services Geographic Information Systems Group

Contact_Position:System Supervisor,GIS

Contact_Address:

Address_Type:mailing and physical address

Address:

621 County Office Building

Address:

524 Forbes Avenue

City:Pittsburgh

State_or_Province:PA

Postal_Code:15219-2952

Country:USA

Contact_Voice_Telephone:412 350-4774

Contact_Facsimile_Telephone:412 350-4754

Metadata_Standard_Name:FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version:FGDC-STD-001-1998

Metadata_Time_Convention:local time

Metadata_Extensions:

Online_Linkage:

Profile_Name:ESRI Metadata Profile