Raster Auto-Vectorization

Automatic raster vectorization significantly improves raster-to-vector conversion efficiency. This method is particularly suitable for raster data with clear linear features. The main operational steps are as follows:

Step 1: Import

Import image data requiring vectorization, which can be loaded as either raster or image data format.

Import Image Files

Step 2: Registration

For raster data without spatial positioning information, spatial registration is required to assign real-world coordinates. This process corrects coordinate systems and projections while rectifying deformations caused during scanning. Detailed registration instructions can be found in the Registration section.

Step 3: Raster Binarization

If raster lines are distinct, binarization may be omitted. Otherwise, perform raster algebra operations: Determine the threshold by observing value differences between lines and background. For example, if line values exceed 10000 while background values are below, use Con(dem > 10000, 1, 0) to convert values to binary 0s and 1s.

Step 4: Auto-Vectorization

  1. Navigate to "Spatial Analysis" tab > "Raster Analysis" group > Click "Vector-Raster Conversion" drop-down > Select "Raster to Vector" to open the dialog.
  2. Select target raster dataset at "Source Data". For pre-binarized data, choose the processed dataset.
  3. In "Result Data" section, specify destination datasource, select result dataset type (Point/Line/Region), and name the output dataset.
  4. When converting to line data, configure these parameters:
    • Smoothing Method: Exclusive to line conversion. SuperMap provides two methods: "B-spline" and "Corner Smoothing". Refer to Smoothing Methods for details.
    • Smoothness: Applies only when smoothing is enabled. For B-spline: Values <2 disable smoothing. For Corner method: Requires values ≥1. Higher values increase smoothness.
    • Thin Raster before Conversion: Enables raster thinning to reduce linear feature width to single cells, improving conversion speed and accuracy. Pre-thinning via Raster Thinning is recommended for wide linear features.

  • Parameters in "Raster Settings" only affect raster dataset conversion:
    • No Value: Cells with specified value are excluded from vectorization.
    • NoValue Tolerance: Extends exclusion range around "No Value" using specified tolerance.
    • Raster Value Field: Stores cell values in specified attribute field (default: "Value").
    • Convert Specified Value Only: Vectorizes only cells matching target value:
      • Raster Value: Exact cell value for conversion.
      • Value Tolerance: Allows value range around specified "Raster Value".
  • Parameters in "Image Settings" only affect image dataset conversion:
    • Background: Excludes specified RGB color from vectorization.
    • Background Tolerance: Defines RGB variation range (0-255) around background color for exclusion. Example: Tolerance=10 excludes colors within R±10, G±10, B±10.
  • Click "OK" to execute or "Cancel" to abort.
    • Figure: Raster to Vector Result

    Note: Automated results often require manual adjustments. Use Feature Editing tools for post-processing operations like adding/deleting/modifying features.