To start automatic line conversion along a raster line
Select Place Element.
Turn on Raster Snap and Auto Convert.
CAUTION: Erase Raster should be turned OFF.
Select the appropriate color mask.
Choose Point or Stream mode.
Choose Line in the Entity option menu.
Enter a data point along the raster line, approximately where you want to begin the line string. The point snaps on the center of the raster line (use the Spy Window with Raster Snap off if you want to define the starting point more precisely).
Enter another data point to determine in which direction you want to go. The automatic line conversion starts automatically from there and continues until a break point (a node, an intersection or an end point) is encountered.
Reset to end the line string (or continue the same line string in the same mode by entering one or more data points.
