Digitizing and Editing Vector Data - Desktop GIS: Mapping the Planet with Open Source Tools - page 73

Figure 5.3: Entering attributes for a feature
gross approximation of the lake, we can just zoom in until we see only
the lake. If we want a detailed representation of the lake, we need to
zoom in much closer and pan around the map as we digitize. We'll take
a middle-of-the-road approach here and zoom in somewhat to illustrate
navigating the map while digitizing.
To start, we zoom in until the lake pretty much fills the map view. To
digitize the lake, click with the left mouse button and begin moving
along the shoreline, clicking at each location where there is a change
in direction. If you get to the edge of the map canvas and need to pan
to continue digitizing, don't use the pan tool; instead hold down the
Spacebar and move the mouse to pan. If you are zoomed in really close,
this technique allows you to work your way around the lake. If you
find out that you need to change the zoom level to effectively digitize,
you can zoom in and out using the mouse wheel. Both of these nav-
igation techniques are discussed in Section D.3 , Map Navigation and
Bookmarks, on page 336 .
You'll notice as you digitize around the lake, the display is updated with
the polygon as you create it. To complete the lake, right-click at the final
point. This opens the attribute dialog box where we enter the attribute
values for the feature. In Figure 5.3 , we have assigned an ID of 1 and
entered “Beach Lake” as the name. When we click OK, these values
will be saved for storage in the . dbf of our shapefile. That completes
Beach Lake; however, the feature hasn't actually been saved yet. To