Understanding GIS: An ArcGIS Project Workbook for ArcGIS 10 Lesson 5: Edit data Correct the shape of an existing feature. Book Resources are located here.
00:01 This is Lesson 5, Edit Data. Exercise 5a, Edit a feature.
00:05 In this exercise we have four objectives.
00:07 First, we want to make sure that, in our map document...
00:09 ...the coordinate system of the data frame is set to match the layer we’re editing.
00:13 In other words, we don’t want to edit data while it’s projected on the fly.
00:17 Second, we’ll start an edit session.
00:19 So we’ll take a look at the various toolbars and windows that go along with that.
00:22 Third, we’ll do spatial editing on a park feature.
00:25 And fourth, after we’ve edited its shape, we’ll update its attributes.
00:30 We’ll start by opening a new blank map.
00:37 We’ll add the Imagery basemap, which we’ll use as a background for editing.
00:45 Open the Catalog window and expand folders down to the ReadyData geodatabase...
00:54 ...and drag the Parks feature class into the map.
00:56 We get a warning because Parks has a different geographic coordinate system from the data frame.
01:01 Close that...
01:02 ...and zoom to the Parks layer.
01:04 Now we’ll add the Data Frame Tools toolbar, which we’ll use a little later.
01:09 Click this button to open the Editing toolbar.
01:13 On the toolbar, we click Editor and Start Editing.
01:16 Here we get an editing warning.
01:18 It tells us that Parks is in a different coordinate system from the data frame.
01:22 Which we already knew.
01:24 But why is it an editing issue?
01:26 Well, most of the time it’s not.
01:28 But the best practice is to edit data in its own coordinate space, not projected on the fly.
01:35 So we’ll stop editing here and address that.
01:38 Open the Data Frame Properties, Coordinate System tab, and expand the Layers folder.
01:44 Expand Parks and click its coordinate system.
01:47 That resets the data frame to California State Plane Zone 5.
01:51 Now the Parks layer and the data frame match.
01:53 Which means Parks is no longer projected on the fly.
01:56 That’s what we want for editing.
01:58 So that takes care of our first objective.
02:00 Except the Parks layer and the basemap still have different geographic coordinate systems...
02:03 ...so they might not line up perfectly.
02:06 We’ll fix that with a geographic transformation here in the data frame.
02:09 We convert from WGS 1984 to NAD 1983 using number 5.
02:15 We did this before in Exercise 4b, except we did it with a geoprocessing tool.
02:20 Click OK and ArcMap won’t give us any more warnings.
02:25 Let’s get to the park.
02:29 Click the My Places button.
02:32 Click Pecan Playground and Zoom To.
02:37 We’ll symbolize the layer with a hollow fill, and a bright green outline.
02:49 And make it a little thicker.
02:54 Adjust the view a little bit.
02:56 Our problem is that the swimming pool and play area at the top should be part of the park...
03:01 ...but they’re not.
03:05 Click Editor, Start Editing. No warning this time.
03:09 We get the Create Features window that lets us automate some things in the editing process.
03:13 But since we’re just editing one feature, we really don’t need it.
03:16 And that completes our second objective, which was to get the edit session going.
03:20 Our third objective is to edit the feature shape.
03:22 Make sure the Edit tool is selected and click the feature.
03:25 Click the Edit Vertices button, which opens another toolbar.
03:28 Now we see the vertices that define the feature’s shape.
03:31 A vertex usually marks a change of angle...
03:34 ...although this park has a couple that don’t.
03:36 Click the Modify Sketch Vertices tool, which lets us move a vertex.
03:41 Place it over this vertex here and drag it to the corner of the field.
03:45 The feature gets reshaped, but we still see the old shape in blue.
03:49 Now take this vertex and drag it up here to the top.
03:56 Change to the Delete Vertex tool and get rid of this useless vertex by drawing a box around it.
04:02 And now we’ll zoom in with the Z key, which you can’t see us pressing.
04:07 Switch back to the Modify Vertices tool...
04:10 ...and drag this red vertex up to the corner of the block.
04:13 The red vertex is the last one that gets added when a feature is created.
04:18 Press the X key to zoom out, C to zoom down, and Z to zoom back in.
04:25 The keys let you navigate without leaving your editing tools.
04:29 We’ll drag this vertex in a little bit from the street.
04:35 And go back to the Delete Vertex tool to get rid of this other bogus vertex.
04:42 Back to our Modify Vertices tool, and pan down here to the bottom...
04:50 ...and drag this last vertex from the street.
04:54 There’s one vertex we haven’t touched yet, which is in a good spot already.
04:59 Let’s just move it around a tiny bit.
05:02 You can feel how it wants to snap to other features, like points or line segments.
05:07 Snapping helps keep features connected, but sometimes it’s annoying.
05:11 You can turn it off in the Snapping toolbar, or zoom in like we’re doing here.
05:15 The snapping tolerance is 10 pixels.
05:18 When you zoom in, 10 pixels takes up more of your screen...
05:21 ...so it’s easier to move around it without snapping to things.
05:24 Let’s go back. The original shape is blue and the edited shape is green. It looks good.
05:30 We’ll click Finish Sketch and save our edits.
05:34 And now for our last objective.
05:36 Since we’ve changed the feature shape, we have to update the area attributes.
05:40 The ACRES value won’t be right anymore.
05:42 Click Show Selected Records.
05:44 Right-click the ACRES field and Calculate Geometry.
05:48 Set the units to Acres and click OK.
05:51 The new value isn’t too different because we made the park longer, but also narrower.
05:58 Again we save our edits.
06:00 Show all records, clear the selection, close the table, and stop editing.
06:12 Finally, we’ll save the map, and name it, and exit ArcMap.
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