Autotracing a Topographical Image

  • You can only trace one image at a time.
  • You can insert topographic images in .bmp, .png, and .jpg formats.
  • Press F3 to disable ESnap. Ths prevents an image from snapping to the wrong point.

To autotrace a topographical image:

  1. Attach a topographical image to a drawing by doing one of the following:
    • On the ribbon, from Drafting and Annotation, click Attach > Image.
    • Enter ATTACHIMAGE at the command prompt.
  2. Enable Topo Tracer by doing one of the following:
    • On the ribbon, from Drafting and Annotation, click Power Tools > Topo Tracer.
    • Enter TOPOTRACE at the command prompt.
  3. Optional: The software automatically detects the profile type of the image. To load a custom profile, in the Topo Tracer pane:
    1. Click the Basic tab.
    2. Under Topographic map profile, click Load Profile.
  4. In the graphics area, use the crosshair to box select the entire image or a part of the image to trace and press Enter.
  5. Click Yes to start autotracing.

    If you click No, you must manually trace the image by using the Tracing options in the Basic tab.

    When autotracing completes, traced lines with zero elevation display in green. Traced lines with a height value display in blue.

  6. Optional: Click the Advanced tab to adjust values for brightness, contrast, transparency, and height scale of the image.
  7. Optional: To fill in gaps, close paths, or apply elevation to individual lines:
    1. Zoom into the image.
    2. In the Basic tab, under Tracing options:
      New Hover over a line and click to manually trace a new line.
      Split Splits a line in two and lets you retrace over line segments.
      Join Red dots indicate gaps. Click red dots to join the ends of two line segments.
      Swap Swaps a line segment with another.
        Base (ground) elevation Specifies a value for the base (ground) elevation.
        Line elevation Selects a point in a line and specifies a value to increase line elevation for a segment.
        Line Thickness Specifies a value in pixels for line thickness.
        Tessellation Specifies the width of the square used to trace a line segment.
    3. Select the Topo line in the graphics area and follow the prompts.
  8. Select mesh, surface, or solid for Landscape Type.
  9. Click Build 3D relief to generate a 3D relief in the drawing.
To improve the display of a 3D relief, in Drafting and Annotation, click View > Shadeview > Flat.