Digital Line Graph (DLG) 1:100,000 Scale Data Dictionary

Coordinates - Decimal Degrees

• Field Definition:  The latitude and longitude are provided in decimal degrees for the following fields:

     Values:

          Scene Center Latitude and Longitude

          Northeast (NE) Corner Latitude and Longitude

          Northwest (NW) Corner Latitude and Longitude

          Southeast (SE) Corner Latitude and Longitude

          Southwest (SW) Corner Latitude and Longitude

          Latitude Format Decimal Degrees: -90.000 through 90.000

          Longitude Format Decimal Degrees: -180.000 through 180.000

          Number of decimal places will vary by dataset – check collection in EE.

Coordinates - Degrees, Minutes, Seconds

• Field Definition:  The latitude and longitude are provided in degrees, minutes, and seconds for the following fields:

     Values:

          Scene Center Latitude and Longitude

          Northeast (NE) Corner Latitude and Longitude

          Northwest (NW) Corner Latitude and Longitude

          Southeast (SE) Corner Latitude and Longitude

          Southwest (SW) Corner Latitude and Longitude

          Longitude Format:

          DDDMMSS.SSH

          DDD = Degree(s) with a range of 0 through 180

          MM = Minute(s) with a range of 0 through 59

          SS.SS = Second(s) with a range of 0 through 59.99

          H = Hemisphere with E for east and W for west

 

          Latitude Format:

          DDMMSS.SSH

          DD = Degree(s) with a range of 0 through 90

          MM = Minutes(s) with a range of 0 through 59

          SS.SS = Second(s) with a range of 0 through 59.99

          H = Hemisphere with N for north and S for south

Coordinate System

• Field Definition:  Code indicating which coordinate system was used when capturing the digital information.

Coordinate Zone

• Field Definition:  Zone of the UTM coordinate system.

Create Date

• Field Definition:  Creation date for the product.

     Format:

          YYYY = Year

          MM = Month

          DD = Day

Data Format

• Field Definition:  The data format can be either Native or SDTS. Native format was formerly known as optional format. Spatial Data Transfer Standard (SDTS) is a language for communicating spatial data which was developed to allow Federal agencies to share spatial data among projects that use different hardware, software and operating systems. The SDTS is a flexible and comprehensive standard that offers the data encoder many options.

Digitizer

• Field Definition:  A reference to persons or organizations who perform digitized work.

Entity ID

• Field Definition:  This field is used to uniquely identify data.

     Example:

          Entity ID: 1J00341ETR002273

     Where:

          1J = Data Set Identifier for DLG

          01341 = Quad Sequence Number

          E = East Half of quadrangle

          002273 = Sequence number within data set.

Half

• Field Definition:  Uniquely identifies which half of the 100K map the data is referring to.

     Values:

     Valid Codes:

          E = East

          W = West

Horizontal Datum

• Field Definition:  A geodetic reference for horizontal control. Five quantities are known: latitude, longitude, azimuth of a line from the point, and two constants that are the parameters for the reference ellipsoid.

Level

• Field Definition:  DLG level code of data quality depending on the specific production process used, such as:

     Values:

          Digital Line Graph - 3 (with all categories of hypsography, hydrography, ridge line, break line, drain files, and all vertical and horizontal control networks).

Map Name

• Field Definition:  This is the 100K quadrangle map name defining a geographic area.

Overlay

• Field Definition:  This field is the two character overlay category defining a geographic area. This field uniquely identifies individual overlay categories for digital line graphs which can be ordered in any combination of unique products.

     Values:

          Following are the overlay categories available and unique codes for each:

          BD = Boundaries

          HP = Hypsography

          HY = Hydrography

          MS = Man-Made Features

          MT = Misc.Transportation

          PL = Public Land Survey System

          RD = Roads

          RR = Railroads

Quad Sequence Number

• Field Definition:  This number is assigned for internal NMD use only.

Resolution

• Field Definition:  Measure of the sharpness of an image or feature.

Revision Date

• Field Definition:  The date of the most recent revision.

Source Date

• Field Definition:  Source date from Header (default).

State

• Field Definition:  This is the two character state abbreviation defining a geographic area.

Status Type

• Field Definition:  "H" stands for Historical (revised by a newer version) data and "A" stands for the recommended (current) data.

Version Number

• Field Definition:  The version number is based on the cell ID, product group, and overlay. If only one product exists per cell ID/product group/ overlay, the version value is 1. If there are more than one product per cell ID/product group/overlay, then for DLG data the following fields are considered in the order listed below:
  
  
  
  Source Date (Most recent date takes precedence)
  
  Revision Date (Most recent date takes precedence)
  
  Level (Highest number takes precedence)