Importing Digital Line Graph (DLG) Files into RockPlot2D

RockPlot2D | File | Import | DLG

Use this tool to import USGS Digital Line Graph data into the RockPlot2D window.

Menu Options
Step-by-Step Summary
DLG Limitations
Tips

Menu Options

• DLG (Input) File: At this prompt, click on the large button to locate the name of the DLG file that the program is to read, accessing other drives and/or directories as necessary. 
• DLG Attributes: Click on this item to view the currently-defined Attribute Table that will be used for the import. The factory default file is named "DLG Attributes" in the program’s System database.   
  • An "Attribute Table" is a file that contains a listing of DLG components and the color, width, and style in which they should be plotted. The program will refer to this Table of information when importing the DLG data. 
  • You can make changes to the Attribute Table, save it under a different file name, etc. See DLG Attribute Tables for more information. 
• Plot undefined entities: Insert a check in this check-box if DLG entities not currently defined in the Attribute Table should still be plotted.  Expand this heading to establish the default properties for these entities.
  • Undefined Line Type: Click on the sample to make a selection. Any undefined entities will be plotted in this line style and color. 
    
    

Step-by-Step Summary

Follow these steps to import a USGS Digital Line Graph file into RockPlot2D. 

1. Be sure there’s a RockPlot2D window open. (See Creating a New RockPlot2D Window.)
2. Select the File | Import | DLG option.
3. Enter the requested menu options, described above.
4. Click the Process button to proceed. 

The program will read the USGS DLG data. It will identify which items are listed in the Attribute Table, and assign them the declared color, line thickness, and line style. It will then determine if you want undefined items to be plotted and, if so, assign them the default characteristics.  See also DLG Import Limitations, below. 

5. Now, you need to tell RockPlot what kind of drawing this is and how to assign the coordinate system (if known).
   
   
   • Choose None if you don't know (or don't particularly care) what kind of drawing this is. This just tells RockPlot that there is no need to geo-reference the image.
     
     
   • Choose Map if this is a map drawing.
     Next you'll be prompted to tell the program what the XY coordinates (map units) are in the AGL file.
     • Choose Undefined if you don't know what coordinate system is represented or if you don't wish to geo-reference the map. The map's coordinates will be brought into the RockPlot window as-is, and without any coordinate projection information.
       ! Without any projection information, you will not be able to export the map from RockPlot2D to Google Earth.
       
       
     • Choose from the other coordinate systems if you know the source coordinates for the drawing; these will be stored in the Rw2D file's metadata. This allows you to geo-reference this image, for output to Google Earth or other software. See Coordinate Systems for more information.
       
       
   • Choose Section or Profile if this is a cross-section drawing.
     As above, you'll be prompted to tell the program whether your XY coordinates (your map units) are.
     • Choose Undefined if you don't know what the original units represent or if you don't wish to georeference this image.
     • Choose from the other coordinate systems if you would like to geo-reference this drawing, for output to Google Earth or other software.
       
       
   • Choose Chart if this is a generic diagram, such as a stereonet or frequency histogram - which has no coordinate reference.
     
     
   • You can click on the Coordinate Summary tab to see the horizontal and vertical diagram extents.
     
     
6. Click OK when you're ready to import the file.

The completed map will be displayed in RockPlot2D.

DLG Import Limitations 

• DLG data is published by the U.S. Geological Survey and must be acquired through them or their agents. DLG data is not provided with this program other than in the form of a sample data file, called "dlg1.dlg."
• The DLG import procedure can read USGS Digital Line Graph data extracted from 1:100,000 or 1:2,000,000-scale maps, Optional format. Boundary, transportation, hydrography, hypsography (contour) and land grid categories are supported. 
• The SDTS format is not currently supported.

Tips

• Use the File | Save command to save the image as a RockPlot "Rw2D" file.
• Use the File | Append command to combine the imported image with an existing Rw2D file (assuming the same coordinate system).
• Use the Utilities | Convert Map Coordinates option to reproject the map to a different coordinate system.
• Once saved as an Rw2D-format file, the DLG map can also be brought into the ReportWorks program for page layout.
   
  

See also:  Working with Layers

Back to Import menu

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