Geography Reference
In-Depth Information
Exercise 5-6 (Project)
Learning Some Editor Fundamentals
Now that you have seen something of the Editor, let's practice using some of its capabilities, and hint at
some others. As I indicated, one could have a whole course on just how to use the Editor. So what you
learn here will necessarily be incomplete. You will be saving very little of your work and nothing that is
significant. This exercise is simply to acquaint you with some of the editing facilities.
The Concept of the Edit Sketch
The Edit Sketch (or Sketch, as we will usually refer to it) is a companion to every line feature or polygon
feature (or feature to be created) in a geodatabase feature class or shapefile. 14 When you want to create
a feature with the Editor, you create a sketch. Once you save your edits, the sketch becomes a feature.
If you are modifying an existing feature, when you make it a target of editing, it is the sketch of the feature
that you are editing. Not until you stop editing the sketch do the modifications take effect on the feature.
Making Sketches with Snapping
1. Start ArcCatalog. By now you know the drill for making feature classes. In
___IGIS-Arc_ YourInitials \Digitize&Transform
\Islands.mdb\UTM_Zone_2
make Edit_Play_Lines and Edit_Play_Polys, each with appropriate Type.
2. Start ArcMap with a Blank Map. Add as data Edit_Play_Lines. Click Start Editing. Let's start by
making a 100 meter long east-west line. A Create Features window may appear on the right side
of your ArcMap window. If it doesn't appear, click on the Editor drop-down window and select
Editing Windows > Create Features. The template should be Edit_Play_Lines. The Construction
Tool should be Line. Move the crosshairs onto the map. Press F6 to bring up the Absolute X,Y
window. Type 500000 for X and 6200000 for Y to make the first vertex. Press Enter.
3. Right-click the data frame and pick Delta X,Y, which will let you give relative coordinates for the
next vertex. Type 100 for X and 0 for Y. Press Enter.
4. At this point all you will see is a red dot. The problem again is one of extent. Instead of zooming
in with the zoom tool, which requires leaving the sketch tool, you can just press and hold the Z
key, which puts the Editor in zoom-in mode as long as the key is held down. 15 Repeatedly drag a
14 The ArcMap Editor cannot be used to edit coverages. You have to use a command-line-driven package called
ARCEDIT, which you find by choosing Start > (All) Programs > ArcGIS > ArcInfo Workstation and typing ARCEDIT
at the arc prompt. Basically, the authors recommend that you convert coverages to geodatabases. Coverages may be
valuable for the data they contain but are fundamentally useless these days as a data structure.
15 There are lots of keyboard shortcuts like this. If you do much editing you will want to know some of them. In the
help interface, you can search for “keyboard shortcuts” or navigate to Professional Library > Data Management >
Editing data > Fundamentals of Editing > Keyboard shortcuts.
 
 
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