NGS Level Lines

Metadata:

• Identification_Information
• Data_Quality_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: NOAA, National Geodetic Survey

Publication_Date: 2004

Title: NGS Level Lines

Edition: latest available

Geospatial_Data_Presentation_Form: Diagram

Series_Information:

Series_Name: N/A

Issue_Identification: N/A

Publication_Information:

Publication_Place: NOAA Campus, Silver Spring, MD

Publisher: NOAA, National Geodetic Survey

Other_Citation_Details:

Questions concerning this data may be addressed to Craig Larrimore EMail - Craig.Larrimore@noaa.gov Phone - 301-713-3257 x152

Online_Linkage: <http://ngsweb.ngs.noaa.gov/cgi-bin/ll2shape.prl>

Description:

Abstract:

The National Geodetic Survey (NGS) serves as the Nation's depository for geodetic data. The NGS distributes geodetic data worldwide to a variety of users. This dataset contains differential leveling observations associated with one of the level lines which was used as input for determining the orthometric heights of one or more vertical control stations maintained by the National Geodetic Survey.

Purpose:

Assist is the analysis of the vertical control network maintained by the Nationsl Geodetic Survey.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: N/A

Currentness_Reference: retrieval date

Status:

Progress: Complete

Maintenance_and_Update_Frequency: Continually

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: 0.0

East_Bounding_Coordinate: 0.0

North_Bounding_Coordinate: 0.0

South_Bounding_Coordinate: 0.0

Keywords:

Theme:

Theme_Keyword_Thesaurus: geodesy

Theme_Keyword: NSRS

Theme_Keyword: geodetic

Theme_Keyword: vertical

Theme_Keyword: benchmark

Theme_Keyword: orthometric

Theme_Keyword: leveling

Theme_Keyword: surveying

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: The geographic limits of USA including trust Territories

Stratum:

Stratum_Keyword_Thesaurus: N/A

Stratum_Keyword: N/A

Temporal:

Temporal_Keyword_Thesaurus: N/A

Temporal_Keyword: N/A

Access_Constraints:

Geodetic Data are in the public domain, not restricted from access or distribution.

Use_Constraints:

Not restricted; Geodetic Data, including software were developed and compiled with U.S. Government funding; no proprietary rights may be attached to them nor may they be sold to the U.S. Government as part of any procurement of ADP products or services.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Craig Larrimore

Contact_Organization: NOAA, National Geodetic Survey

Contact_Position: IT Specialist

Contact_Address:

Address_Type: Mailing and Physical Address

Address:

SSMC2/9152 1315 East-west Highway

City: Silver Spring

State_or_Province: MD

Postal_Code: 20910

Country: USA

Contact_Voice_Telephone: 301-713-3257x152

Contact_Facsimile_Telephone: 301-713-4172

Contact_Electronic_Mail_Address: Craig.Larrimore@noaa.gov

Hours_of_Service: 8:30am to 5:00pm EST

Contact_Instructions: Prefer EMail

Data_Set_Credit:

NOAA, National Geodetic Survey and cooperating organizations

Security_Information:

Security_Classification_System: DOD

Security_Classification: unclassified

Security_Handling_Description: none

Native_Data_Set_Environment:

The data was extracted from NGS database and is available at <http://ngsweb.ngs.noaa.gov/cgi-bin/ll2shapefile.prl>

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

The Level Lines were established in accordance with FGDC publications "Standards and Specifications for Geodetic Accuracy Standards"

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value: 95 percent confidence level for geodetic quality data.

Attribute_Accuracy_Explanation:

Geodetic Data are continuously being processed; their standards and specifications are being reviewed for next publication release. "Standards and Specifications for Geodetic Control Networks", 1984 and "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0 1989, are most current published documents.

Logical_Consistency_Report:

FGCS sponsored testing in cooperation with equipment manufacturers and National Institutes of Standards and Technology, Gaithersburg, MD 20850

Completeness_Report:

This dataset contains all level line observations for the HGZ specified, including rejected observations and/or observations to non-publisable marks. <http://ngsweb.ngs.noaa.gov/cgi-bin/craigs_lib.prl?HELP_NONPUB=1>

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report: +/- 180 meters

Quantitative_Horizontal_Positional_Accuracy_Assessment:

Horizontal_Positional_Accuracy_Value: +/- 180 meters

Horizontal_Positional_Accuracy_Explanation:

In most cases the xy coordinate used to identify the endpoints of each line of observation where obtained by scaling the points on a topographic map and may be in error by as much as 180 meters.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

The description of tests are explained in "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," FGCS (formally FGCC) publication version 5.0, 1989, (See table 1, p6).

Quantitative_Vertical_Positional_Accuracy_Assessment:

Vertical_Positional_Accuracy_Value: Best vertical accuracy assumed to be +/- .5 mm

Vertical_Positional_Accuracy_Explanation:

The level lines are assigned an ORDER anc CLASS stored in attributes LINE_ORDER and LINE_CLASS

which are descripbed in FGDC publication

"Standards and Specifications for Geodetic Accuracy Standards"

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: NOAA, National Geodetic Survey

Publication_Date: N/A

Title:

"Input Formats and Specifications of the National Geodetic Survey Data Base" published by FGCS (formally FGCC)

Edition: latest available

Geospatial_Data_Presentation_Form: diagram

Series_Information:

Series_Name: N/A

Issue_Identification: N/A

Publication_Information:

Publication_Place: NOAA Campus, Silver Spring, MD

Publisher: NOAA, National Geodetic Survey

Other_Citation_Details: N/A

Online_Linkage: <http://ngsweb.ngs.noaa.gov/FGCS/BlueBook/>

Type_of_Source_Media: paper, Web

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1994

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Blue Book

Source_Contribution:

The geodetic data must be submitted in the digital formats specified in the FGCS (formally FGCC) publication "Input Formats and Specifications of the National Geodetic Survey Data Base" which describes the formats and procedures for submission of data for adjustment and assimilation into the National Geodetic Survey Data Base. Separate volumes of this publication refer to horizontal (volume 1), vertical (volume 2), and gravity (volume 3) control, and are available from NOAA, National Geodetic Survey, 1315 East-West Hwy, Code N/CGS1, Silver Spring, MD, 20910 (1-301-713-3242). Note guidelines for submission of three-dimensional Global Positioning System (GPS) relative positioning data are contained in annex L to volume 1.

Process_Step:

Process_Description:

The National Geodetic Survey produces geodetic data. Geodetic data comprise the results of geodetic surveys to determine, among other things, latitude, longitude, height, scale, and orientation control. The National Geodetic Survey original field survey project observations and final reports are accessioned into records system of the National Archives and Records Administration of the U.S.A. These surveys provide information valuable for a variety of uses in the mapping, charting and surveying community.
The NGS' stored level line observational data in the NGS database. These observational data are used to compute new orthometric heights for vertical control stations maintained by the National Deodetic Survey.
This dataset contains certain information extracted from the stored level line observational data mentioned above.

Source_Used_Citation_Abbreviation: Geodetic Data

Process_Date: Not complete

Source_Produced_Citation_Abbreviation: NOAA, National Geodetic Survey and cooperating organizations.

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Craig Larrimore

Contact_Position: IT Specialist

Contact_Address:

Address_Type: Mailing and Physical Address

Address:

SSMC2/9152 1315 East-west Highway

City: Silver Spring

State_or_Province: MD

Postal_Code: 20910

Country: USA

Contact_Voice_Telephone: 301-713-3257x152

Contact_Facsimile_Telephone: 301-713-4172

Contact_Electronic_Mail_Address: Craig.Larrimore@noaa.gov

Hours_of_Service: 8:30am to 5:00pm EST

Contact_Instructions:

Prefer EMail Spatial_Reference_Information

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: North American Vertical Datum of 1988 (NAVD 88),

Altitude_Resolution: 1.0

Altitude_Distance_Units: meters

Altitude_Encoding_Method: implicit coordinate

Depth_System_Definition:

Depth_Datum_Name: Land survey datum

Depth_Resolution: 1.0

Depth_Distance_Units: meters

Depth_Encoding_Method: implicit coordinate

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

The current attributes and their meaning are shown below.


#FeatureId
Temporary unique ID assigned to this station.


DATA_DATE-
The date when this information was retrieved from the NGS database.


DATA_SRCE-
Data Source where the information for the level line came from.


START_X-
Decimal equivalent of the LONGITUDE for the START_PID point
of the observation.
Always displayed to 5 decimal places,
but should be considered to be in error by +/- 180 meters.


START_Y-
Decimal equivalent of the LATITUDE for the START_PID point
of the observation.
Always displayed to 5 decimal places,
but should be considered to be in error by +/- 180 meters.


END_X-
Decimal equivalent of the LONGITUDE for the END_PID point
of the observation.
Always displayed to 5 decimal places,
but should be considered to be in error by +/- 180 meters.


END_Y-
Decimal equivalent of the LATITUDE for the END_PID point
of the observation.
Always displayed to 5 decimal places,
but should be considered to be in error by +/- 180 meters.


HGZ-
Project identifier assigned to the level line by NGS.


LINE_START-
Unique identifier of the first station in entire level line.
Not to be mistaken for START_MARK which is the identifier
for the StandPoint of the backsight-foresight observation


DATE_STARTED-
Date of the first observation for the  entire level line (YYYYMMDD).


DATE_END-
Date of the last observation for the  entire level line (YYYYMMDD).


LINE_ORDER-
Order of accuracy for the entire level line.


LINE_CLASS-
Class of accuracy for the entire level line.


OBS_ID-
Unique integer assigned by NGS to identify the
observation within the project.


START_MARK-
Unique identifier of the StandPoint of the backsight-foresight observation.
Not to be mistaken for LINE_START which is the identifier
for the first station in entire level line.


END_MARK-
Unique identifier of the ForePoint of the backsight-foresight observation.


OBS_DATE-
Date of the backsight-foresight observation (YYYMMDD)
Not to be mistaken for the START_DATE of END_DATE
which refers to the entire level line.


LENGTH-
The distance between the START_MARK and END_MARK
in units of LEN_UNITS.


LEN_UNITS-
Units LENGTH was measured in.
FT = FEET
KF = KILOFEET
KM = KILOMETERS
MT = METERS
SM = STATUTE MILES
YD = YARDS


OBS_DIFF-
Uncorrected height difference measured between START_MARK and END_MARK


DIFF_UNITS-
Units of measurement for OBS_DIFF


OBS_REJECT-
Indicates if the observation was rejected
N = NOT REJECTED
F = REJECTED IN THE FIELD
O = REJECTED IN THE OFFICE
R = REJECTED IN THE "REDUC" PROGRAM

Entity_and_Attribute_Detail_Citation:

All values were obtained from the NGA Datasheet available at <http://ngsweb.ngs.noaa.gov/cgi-bin/ll2shapefile.prl>

Distribution_Information:

Distributor:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Craig Larrimore

Contact_Organization: NOAA, National Geodetic Survey

Contact_Position: IT Specialist

Contact_Address:

Address_Type: Mailing and Physical Address

Address:

SSMC2/9152 1315 East-west Highway

City: Silver Spring

State_or_Province: MD

Postal_Code: 20910

Country: USA

Contact_Voice_Telephone: 301-713-3257x152

Contact_Facsimile_Telephone: 301-713-4172

Contact_Electronic_Mail_Address: Craig.Larrimore@noaa.gov

Hours_of_Service: 8:30am to 5:00pm EST

Contact_Instructions: Prefer EMail

Resource_Description: Datasheet Shapefile

Distribution_Liability: The distributor does not assume liability

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: ShapeFile

Format_Version_Number: 0.3.0

Format_Version_Date: 1999

File_Decompression_Technique: Download options include PC Zip and Unix compressed tar

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://ngsweb.ngs.noaa.gov/cgi-bin/ll2shapefile.prl>

Access_Instructions: Must have access to NGS internat IntraNet

Online_Computer_and_Operating_System: SUN Solaris

Fees: free if you retrieve it yourself

Metadata_Reference_Information:

Metadata_Date: 20040129

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Craig Larrimore

Contact_Organization: NOAA, National Geodetic Survey

Contact_Position: IT Specialist

Contact_Address:

Address_Type: Mailing and Physical Address

Address:

SSMC2/9152 1315 East-west Highway

City: Silver Spring

State_or_Province: MD

Postal_Code: 20910

Country: USA

Contact_Voice_Telephone: 301-713-3257x152

Contact_Facsimile_Telephone: 301-713-4172

Contact_Electronic_Mail_Address: Craig.Larrimore@noaa.gov

Hours_of_Service: 8:30am to 5:00pm EST

Contact_Instructions: Prefer EMail

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time

Metadata_Access_Constraints:

Geodetic Data are in the public domain, not restricted from access or distribution.

Metadata_Use_Constraints:

not restricted; Geodetic Data, including software were developed and compiled with U.S. Government funding; no proprietary rights may be attached to them nor may they be sold to the U.S. Government as part of any procurement of ADP products or services.

Metadata_Security_Information:

Metadata_Security_Classification_System: DOD

Metadata_Security_Classification: unclassified

Metadata_Security_Handling_Description: none

Metadata_Extensions:

Online_Linkage: N/A

Profile_Name: N/A