Heads-Up Digitizing - 1

The following is a listing of how to do this using ARC/INFO. All commands for ARC/INFO will be printed in bold here. In this example, a polygon representing an ownership parcel will be split and another combined using a background stream coverage as a guide. The polygon with label id = 84 will be split into two parcels along the stream while the two parcels (86 and 192) will be combined. The accuracy of the map is degraded enough to allow simple editing and on-screen digitizing.

  1. Starting from your operating system prompt type ARC

    2.  

  2. When ARC Info starts, type: lc or listcoverages

    3. A list of all valid coverages in your current directory will be returned: 

    Arc: lc
 Workspace:        C:\ARCDATA\EX8

 Available Coverages
 -------------------
  HYDRO	 ROADS	PARCEL

     

  3. To enter ARCEDIT and set the display, type: arcedit and display 9999

    4. This will look something like this: 

    

    Arc: arcedit
    

    Copyright (C) 1982-1997 Environmental Systems Research Institute, Inc.
    

    All rights reserved.
    

    ARCEDIT (COGO) Version 7.1.1  (Thu Feb  6 23:26:50 PST 1997)
    

    Arcedit: display 9999
    

     
    

  4. Set up the edit coverage, the drawing environment, and map extent to begin digitizing.
    5. 

    Arcedit: edit parcel
    

    The edit coverage is now C:\ARCDATA\EX8\PARCEL
    

    Arcedit: drawenvironment all label ids
    

    Arcedit: mapextent 338697,4459053,345945,4464543
    

     
    

     
    

  5. Set the background coverage with  color 4, (blue).
    6. 

    Arcedit: backenvironment arc on
    

    Arcedit: backcoverage hydro 4
    

    C:\ARCDATA\EX8\HYDRO is now background coverage 1 with draw symbol 4
    

     
    

     
    

  6. The graphical interface should look something like this.
    7. 

  7. Judging from this image, it is clear that the stream is dividing parcel 86 from 192 and could be used to reference the edit session and successfully delete the arc.  To do this, merely set the editfeature and select the arc, then delete it.
    8. 

    Arcedit: editfeature arc
    

    252 element(s) for edit feature ARC
    

    Coverage has no COGO attributes
    

    Arcedit: select one
    

    Point to the feature to select
    

    Enter point
    

    Arc 143 User-ID: 38561029 with 9 points
    

    1 element(s) now selected
    

    Arcedit: delete
    

    1 arc(s) deleted 
    

    Arcedit: draw
    

     
    

    8. So far, the hydro coverage has been used as a reference location to determine that the line to be deleted was indeed along the stream boundary.  Next, a new line will be digitized on the screen using the mouse and keyboard input.  This is similar to using a digitizer with a tablet and cursor puck.  In the on screen digitizing process, the vertex and node keys are on the keyboard rather than the digitizing puck.
    

    Arcedit: editfeature arc
    

    251 element(s) for edit feature ARC
    

    Coverage has no COGO attributes
    

    0 element(s) now selected
    

    Arcedit: nodesnap first 10
    

    Arcedit: intersectarcs add
    

    Arcedit: add
    

    --------------------Options--------------------
    

     1) Vertex              2) Node                3) Curve
    

     4) Delete vertex       5) Delete arc          6) Spline on/off
    

     7) Square on/off       8) Digitizing Options  9) Quit
    

    (Line) User-ID: 38564036 Points 0
    

     
    

  8. Here is what the display would look like: 
    9. 

  9. All techniques learned to edit and digitize coverages still apply when you are digitizing on-screen.  The final stage of this example would be to finish the arc, edit any dangling nodes and then add the missing label point to the new polygon.
    10. 

  10. In this exercise, one coverage was used to edit and add new information to another coverage.  This example utilizes rudimentary techniques in on-screen digitizing.





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