Import From DLG (Coverage)


Converts a Standard or Optional formatted Digital Line Graph (DLG) file to a coverage.



DLGArc_arc (in_dlg_file, out_cover, {out_point_cover}, {area_calculation}, {x_shift}, {y_shift}, {category})
ParameterExplanationData Type

The DLG file to be converted to a coverage.


The name of the coverage to be created from the DLG data. If the input DLG file contains data produced by the United States Geological Survey (USGS), the output coverage will usually contain line, polygon, and node features created from nondegenerate line (L) records, area (A) records, and node (N) records. An Output Coverage.NAT for node features will be created.

This is the only feature attribute table that is created by Import From DLG.

An INFO table named Output Coverage.ACODE will be created that contains the major/minor pair values for all line (L) records. Similarly, an INFO table named Output Coverage.PCODE will store the major/minor codes for area (A) records.


The name of an Optional point coverage to be created from degenerate line (L) records in the DLG. In a DLG, points are stored as zero-length arcs (that is, degenerate lines).

These are optionally converted to points by specifying an output point coverage. An INFO table named Output Point Coverage.XCODE will be created, which contains all major and minor code pair values for degenerate line (L) records.

No coverage will be created from degenerate line records unless an Output Point Coverage is specified.


Determines how the area (A) records are written to the output coverage.

  • NOFIRSTThe first area record is ignored. Labels are written for all other area records and the corresponding major/minor codes are written to the Output Coverage.PCODE file. This is the default option.
  • ALLAll area records are converted to output coverage label points and the major and minor codes for all area (A) records in the Output Coverage.PCODE file. Usually the label point for the first area record is in the outside polygon.
  • ATTRIBUTEDThe label location in the DLG file is used only for those area records that carry major/minor codes. For some DLG categories, only area records with attributes have valid label locations. The first area (A) record is not included.

A constant value to be added to all x coordinates during DLG conversion. The default X Shift value is zero.


A constant value to be added to all y coordinates during DLG conversion. The default Y Shift value is zero.


The optional name of a specific DLG category to be converted from the DLG file. Only the specified category will be converted if one is given. Otherwise, only the first category in the DLG will be written to the output coverages: output coverage, point coverage.


Code Sample

DLGArc example (stand-alone script)

The following stand-alone script demonstrates how to import a coverage from DLG format.

# Name:
# Description: Imports from DLG format to a coverage
# Requirements: ArcInfo Workstation
# Author: ESRI

# Import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data"

# Set local variables
inDlgFile = "509954.PL.opt.dlg"
outCover = "C:/output/954netcov"
outPointCover = "C:/output/954pointcov"

# Execute DLGArc
arcpy.DLGArc_arc(inDlgFile, outCover, outPointCover, "", "", "", "")


Related Topics

Licensing Information

ArcView: No
ArcEditor: No
ArcInfo: Requires ArcInfo Workstation installed

Published 6/8/2010