ArcScan is designed to work in conjunction with the ArcMap editing environment and is only active when an edit session has been started. The editing tools, commands, and dialog boxes related to ArcScan are described below.
Starting an edit session
You must start an edit session to activate the ArcScan toolbar and gain access to its tools and commands. If you enable the ArcScan extension while already in an edit session, you must stop editing and restart the edit session to use ArcScan. Click the Editor menu and click Start Editing to begin an edit session.
Snapping to rasters
Raster snapping allows you to accurately create features that follow lines in rasters. The ability to snap to connected cells can help make interactive vectorization more efficient. You can choose to snap to the following locations of raster connected cells: centerlines, corners, ends, intersections, and solids.
ArcScan uses the classic editing snapping environment rather than the settings on the Snapping toolbar. You must enable classic snapping on the Editing Options dialog box. The raster snapping properties that support the manual vectorization process are located in the Snapping Environment window under the Raster tree. Click the Editor menu, point to Snapping, then click Snapping Window to display the Snapping Environment window.
ArcScan also uses the settings for snap tolerance and whether to show SnapTips in the map. The editing snapping tolerance applies to both vector and raster snapping properties. Click the Editor menu, point to Snapping, then click Options to change those settings.
Using feature templates
Vector features generated by raster tracing will be written to the active feature template on the Create Features window, which is opened from the Editor toolbar. It may be necessary to switch the target template when you are creating both line and polygon features during raster tracing. You may also change the target if you want to vectorize portions of the raster to different vector layers. When you are using automatic vectorization, you can choose the template to use to create new features from the Generate Features dialog box.
Setting the stream tolerance
ArcScan uses the editing options for the current stream tolerance when tracing features. Click the Editor menu and click Options to display the Editing Options dialog box.
Using sketch construction methods
In addition to the ArcScan raster tracing tools, you can also use the Create Features window construction tools and Editor toolbar sketch construction methods to trace raster cells and gain greater control regarding the creation of vertices. The construction tools use the current raster snapping settings to ensure accuracy when creating features.
Undoing and redoing edits
All ArcScan operations can be reversed by using the Undo command. In addition, the Redo command reverses the operation previously negated by the Undo command.
Utilizing additional editing tools to edit vectorized features
In addition to the tools and commands available on the Editor toolbar, ArcGIS supports a variety of specialized tools to further extend its editing functionality. These include tools for topology, advanced editing, and spatial adjustment that can assist with editing features once you have completed the vectorization. Click the Editor menu and point to More Editing Tools to access them.
When you are satisfied with the results of the vectorization, save the edits to retain the features and changes you have made to them. You can periodically save edits or wait until you have finished your edit session. Click the Editor menu and point to Save Edits, then click Yes.