USGS Digital Line Graph Boundary [.DLG] Import Automation Options

Since the Import Options dialog is not displayed when the program is driven from an automation script, an options string can be specified in the script. The string consists of comma-separated parameters, which specify the behavior of the various import options. Parameters for the Attributes list box, Range and List radio buttons are not available. If the program is driven from a script, use MajorSel and MinorSel parameters instead. A typical example would be:

"Defaults=1,AreasToCurves=1"

This would first set all import options to their default values, then set the AreasToCurves option value to one, which would specify that any areas imported be converted to closed curves.

Option

Action

Default

Description

AllNodes

0 = No

1 = Yes

0

Import all nodes (point entities).

FreeNodes

0 = No

1 = Yes

0

Import only free-standing nodes (points that aren't part of another entity).

AllAreas

0 = No

1 = Yes

1

Import all areas (polygons).

NoMapFrame

0 = No

1 = Yes

1

Don't import the entities that make up the map frame.

AreasToCurves

0 = No

1 = Yes

0

Convert areas (polygons) to curves (polygons).

AllLines

0 = No

1 = Yes

0

Import all lines.

FreeLines

0 = No

1 = Yes

1

Import only free-standing lines (lines that aren't part of another entity).

Synthesize

0 = No

1 = Yes

0

If 1, a unique object ID is synthesized for each object form the object's type, record number, an d name (if applicable).

Projection

0 = Coordinates in the file are projected (UTM or Albers Equal Area projection, depending on the file)

1 = Coordinates in the file are projected, but are to be converted to latitude/longitude during import

2 = Coordinates in the file are unknown or not projected

Varies according to the DLG header information

Specify what type of coordiantes are contained in the import file.

IDSel

M-N

 

Only consider entities with IDs matching M, or in the range of M-N. For example, "IDSel=1-5".

MajorSel

M-N

 

Only consider entities whose Major Attribute is M, or in the range of M-N. For example, "MajorSel=1-5".

MinorSel

M-N

 

Only consider entities whose Minor Attribute is M, or in the range of M-N. For example, "MinorSel=1-5".

ThinAuto

0 = No

1 = Yes

1

Automatically thin vertices.

Deviation

N.N

0.0

If ThinAuto (above) is 0, you can manually specify the amount of thinning. The Deviation value in degrees determines how aggressively vertices are thinned during import. For N.N, use small angles (5 to 10 degrees) to eliminate just a few points, larger angles (15 to 25 degrees) to eliminate more points, and even larger angles (30 to 60 degrees) to thin points very aggressively.

See Also

Import Options String

USGS Digital Line Graph File Description

USGS Digital Line Graph Boundary Import Options Dialog