Document: Digitizing in ArcGIS
Created: 10/08/02 (Tom Evans)

The following document presents simple instructions for digitizing features in ArcMap.

This document assumes the existence of a background raster dataset (named "source") which depicts features to be digitized and a new Geodatabase/Feature Class (named "forest") in which the new digitized features will be created.

Step 1) Add source and forest to your ArcMap session (In most cases it is advised you do this in a new ArcMap session)

Step 2) Turn on Editor toolbar in ArcMap

In ArcMap select View : Toolbar : Editor

If you can not select the feature class you want to edit it may be because you are modifying it in ArcCatalog or in another session. Close all other Arc Modules (ArcCatalog) to be sure this is not the source of the problem.

Step 3) Select the layer to which features will be added

On Editor Toolbar set the Target to forest

Step 4) Zoom to the feature to be digitized

Step 5) Select the Create New Feature tool from the Editor Toolbar (pencil)

Step 6) To create a polygon feature left-click once in the dataframe to start a new polygon. Successive single left-clicks will create vertices. Double-click at the last vertex to create a closed polygon.

If you are editing a point feature class simply single-left-click to add a single point location

If you are editing a line feature single-left-click to start a new line, successive single-left-clicks add vertices, end the line with a double-left click

If you are in the middle of editing a line and realize that you want to make a correction to a part of that line you have already completed, double click to finish the line segment. Then select the Edit tool (the black arrow just to the left of the 'pencil' in the Editor toolbar), using this tool you can select a feature (double-click on a polygon) and move the vertices individually.

Note, the Escape key often can get you out of a particular step that you get stuck in the middle of.

There is an Undo feature (Ctrl-Z or Edit : Undo - from the main menu) that is quite helpful. If your polygon gets too complicated to fix you can select it (using the Edit tool) and delete it (select then press the delete key).

Step 7) Repeat Step 6 as needed until all features are digitized. Note, you can pan and zoom while in the middle of digitizing a feature. Another handy feature is the Magnifier Window (open this by selecting Window : Magnifier - from the main ArcMap menu bar) which allows you to have a separate window zoomed into a portion of the main Data Frame. You can pan and zoom this window around your Data Frame which is a convenient way to follow the path of a long feature.

Note these instructions for creating Island polygons

FREQUENTLY SAVE YOUR EDITS DURING YOUR EDIT SESSION

From Editor toolbar select Editor : Save Edits

NOTE: Selecting File : Save - from the main ArcMap menu DOES NOT SAVE YOUR EDITS. It only saves the settings in your current work session (the list of features in your table of contents and data frame, the symbols you've used to draw them, the extent to which you are zoomed...). Saving the session in this way is helpful to save you time when you set the symbolization for a data frame that will have a lot of features but does nothing to modify/save/edit the data - only the session...

Step 8) Once you have digitized all features save your edits

From Editor toolbar select Editor : Save Edits

Step 9) Stop Editing

From Editor toolbar select Stop Editing is polygon.