Geographic and Attribute Data: Selection, Input, and Editing - Introducing Geographic Information Systems with ArcGIS - page 332

2. In ArcMap open the map named North_Islands_map3. Add as data the geotif file
IGIS-Arc\Image_Data\MSH
This is a pretty big file, so build pyramids if asked, which takes a bit of time now but results in
faster access in the future. Zoom to the MSH image.
3. As you observe the image, you can imagine that you see two triangular harbors along the south
coast. Using the Georeferencing toolbar (don't forget to turn Auto Adjust off), move the apex of
the southwest harbor to (Easting 630000, Northing 4100000) and the southeast harbor apex
to (Easting 660000, Northing 4100000). View the Link Table to be sure you have the right
coordinates in. Turn on Auto Adjust so the move happens. When the move is complete, zoom to
the image. Then zoom to full extent to see where this new island is with respect to the others.
Recall that you previously digitize the five islands as lines and then converted the lines to polygons. When
you did this, the polygons that were created obeyed rules that resulted in no overlaps and no gaps. There
are several ways to add the new island to North_Island_Polygons, but let's use one in which you digitize
polygons directly into the geodatabase feature class.
4. Start editing. The target should be North_Island_Polygons. You want to create new polygons.
Zoom to MSH. Digitize first the outline of the island. When digitizing polygons with curved lines,
use more points along the lines where the curvature is greatest. See Figure 5-15.
FIGURE 5-15 The sixth island