How To: Understand Stream Mode Digitizing

Procedure

Summary

Understanding some key factors behind stream mode digitizing will help you understand how to use it more effectively.

Discussion

Digitizing under the windows extensions (ARCEDITW) works slightly differently than under DOS (ARCEDIT). ARCEDIT displays the line constantly during digitizing, where as ARCEDITW does not. This is because drawing all the little line segments during digitizing can slow down the process by a factor of 2. You can, however, display the line at any point. This will be discussed in more detail later.

Using a compatability box in Windows (3.x, 95, or NT) is not the same as running in DOS. You should not run ARCEDIT or DIGTEST in a DOS compatability box, nor at the ARC prompt under Windows (3.x, 95, or NT). Otherwise you will get lots of beeps and lost digitized points. Misunderstanding this may lead you to believe PC ARC/INFO is digitizing poorly.

Before you can do stream mode digitizing, you must set up the digitizer format file to enable stream mode digitizing. Some of digitizing format files are not set up for stream mode; thus, it can be misconstrued as PC ARC/INFO not being capable of stream mode digitizing.

If the digitizer format file is not set up for stream mode, you can do only point mode digitizing. ARCEDIT and ARCEDITW operate slightly differently:

  Cursor tracking
    In ARCEDIT and ARCEDITW, you can track the cursor by pressing
    the "0" key or the key that sends a "0".

  Line Drawing
    In ARCEDIT, pressing the "1" key draws each line segment on the screen.
    In ARCEDITW, a line segment is not drawn until either a "0" or "2" key is
    pressed. In other words, you can see what the line looks like by pressing
    the "0" or ending the line with a "2" key.

If the digitizer format file is setup for stream mode, you can do either point or stream mode digitizing. In ARCEDIT and ARCEDITW use the "*" key to switch back and forth. ARCEDIT and ARCEDITW operate slightly differently:

  Point mode
    Cursor tracking
      ARCEDIT constantly tracks the cursor.
      ARCEDITW does not. You need to press the "0" key.
      
    Line drawing
      In ARCEDIT, as you press the "1" key, each line segment is drawn on the screen.
      In ARCEDITW the line segments are not drawn until either a "0" or "2" key is pressed.
      In other words, you can see what the line looks like by pressing the "0" or ending
      the line with a "2" key.

  Stream mode
    Cursor tracking
      Both ARCEDIT and ARCEDITW track the cursor.

    Line Drawing
      ARCEDIT draws the each line segment immediately as it is added a line.
      ARCEDITW draws the line segment(s) when you release the "1" key or press the "0" or "2" key.

The main difference between ARCEDIT and ARCEDITW in this regard is the immediate drawing of the line as it is digitized. The reason it is not done in ARCEDITW is that it slows down digitizing. It can also be argued that during stream mode input (holding down the "1" key) you should be looking at your map and cursor to get accurate results and at that point you don't need to see what is on the screen. When you release the "1" key and no points are recording, then the screen is updated. One suggestion if you want to do point mode digitizing and want to see the line drawn constantly is to switch to stream mode and set a weed tolerance, then when you release the "1" key, the line is drawn. The weed tolerance will prevent you from getting extra points.

Article ID:000001630

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Understand stream mode digitizing

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