Working with Spatial Data in ArcGIS丂Lesson2

Table of ContentsLesson goalsTopic: Editing featuresConceptsGeneral editing principlesWorking with sketchesUsing the Sketch menuBasic editing toolsUsing the ArcMap Integrate command ExerciseEdit features with the Editor toolbar Lesson summaryLesson self testTable of ContentsLesson goalsIn this lesson you will learn:∙how to start an editing session∙about the tools available on the Editor toolbar∙how to work with sketches∙what the ArcMap Integrate command doesTopic: Editing featuresEditing feature geometry is a common task when you work with a GIS. Often, you need to edit inaccurate digital data to reflect real-world feature shape, size, and location. ArcMap provides convenient tools to assist you with editing features.ConceptsGeneral editing principlesBefore you can edit your data, you need to add the Editor toolbar to the ArcMap window to start and stop your edit sessions. The Editor toolbar contains many of the tools you'll use to edit your data.The Editor toolbar contains most of the tools you'll use when editing your data.All editing takes place within an edit session. The general process for editing in ArcMap is to start an edit session, make your changes, stop the edit session and, optionally, save your changes. All changes you make while you're in an edit session are immediately visible on your map. Saving the map does not automatically save the changes you made to your data.The Start Editing dialog shows your available workspaces and layers.When you start an edit session, ArcMap displays the Start Editing dialog shown above. Clicking on each available folder or geodatabase shows you which layers are available for editing.Working with sketchesIn ArcMap, every feature's geometry is represented by a sketch. A sketch consists of vertices (the end points of line segments, which normally indicate a change in direction) and segments (the lines that connect the vertices). When you edit a feature in ArcMap, you are working with its sketch, not the original features. ArcMap allows you to edit existing features or create new ones in an existing feature class. To create a new feature class, you use ArcCatalog.At top, a feature has been highlighted.Below is the feature's sketch. Vertices aredisplayed with green boxes. The red box isthe last vertex that was added when thefeature was created.To create a new feature, you must first create a sketch. Likewise, to edit a feature, you must edit its sketch. When you save, the feature is updated with the changes you made to its sketch. You can create only line and polygon sketches, because points have neither vertices nor segments.Using the Sketch menuMany of the editing tasks you use in ArcMap are available through two context menus. The Sketch context menu appears when you right-click while the mouse pointer is on a vertex or segment of a sketch.When editing a sketch, right-click toaccess the Sketch context menu.The other context menu, the Sketch Tool context menu, is available while you're creating a sketch with the Sketch tool.The Sketch context menu works more directly with the sketch as a whole. For example, you can insert or delete vertices. Below, a vertex has been inserted along the top segment of the sketch.The Insert Vertex command inserts a vertex at the location where youright-clicked to display the Sketch context menu.You can move a vertex by dragging the vertex to a new location, specifying a change in its x,y coordinates (a delta X,Y), or specifying a new x,y location for the vertex.The red vertex is moved to 0, 50.You can change the direction of a sketch using the Flip command. New segments of a sketch are added from the last vertex, usually indicated in red. Flip inverts the sketch so that the first vertex becomes the last. In other words, Flip changes which end of the line segment you're working with, and you can add new vertices from there.Right-click and choose Flip to invert a sketch.To modify the length of a sketch, use the Trim command. The end of the sketch will be trimmed according to the length you specify.Trim cuts off the sketch by the amount you specify.When your sketch is complete, choose Finish Sketch (or double-click) to finish the sketch. In the graphic below, the sketch is being used to modify the shape of a polygon. The polygon's shape does not change until the sketch is finished.Finish Sketch passes the geometry of the sketch to the feature.Basic editing toolsOnce you've started an editing session, there are many tools available for editing your data. You can use the tools on the Standard toolbar to cut or copy and paste features across layers, delete features, and undo and redo changes. You can undo changes back to your last save.The ArcMap Standard toolbarcontains familiar Windows editingtools.The Editor toolbar contains many of the tools you'll use for editing. The Edit tool selects, moves, and modifies the shape of features in the layers marked as selectable.Before you can edit features in a layer, you must make the layer"selectable."The selectable layers are set in the Selection menu. In the graphic above, street, citylimit, Lines, and SubdivisionParcels are all selectable.Use the Shared Edit tool to maintaintopological associations among all thefeature classes in a feature dataset.The Shared Edit tool is similar to the Edit tool, but it allows you to maintain topological associations. The Shared Edit tool lets you move coincident geometry in a feature dataset. Before you use the Shared Edit tool, you should run the Integrate command from the Editor menu. The Integrate command helps ensure that your dataset is topologically correct by making features coincident within a distance range you set.The Shared Edit tool adjustscoincident vertices andboundaries in all featureclasses contained in afeature dataset at once.When you select with the Shared Edit tool, only the top-most visible vertex or boundary on the map will be highlighted. However, every vertex or boundary in the dataset below where you clicked on the map is actually selected. This ensures that when you move part of a feature that is shared, any coincident vertices or boundaries underneath will move appropriately, as well as any vertices or boundaries connected to those parts. This is true even for feature classes that aren't visible.The Rotate tool rotates selected features around a selection anchor. The "X" in the graphic below is the selection anchor. You can click and drag your mouse pointer to rotate features, or you can press A on the keyboard and specify an exact rotation angle. You can also move the selection anchor."X" marks the selection anchor.The Split tool splits a line feature into two features. First, you must select the line, then you can use the Split tool to click on the location where you want the line to be split. If you use the default split policy, the attributes of the original line are copied to each of the new lines.The Split tool splits a line at the place where you click. Each sideflashes to let you know there are two new features.The Sketch tool is one of the tools you can use to create a sketch. A sketch is displayed as a series of vertices and segments. You'll use sketches in many of your editing tasks. Sketches can be used to create new features, select features, reshape features, and for many other operations.The sketch for this polygon has six vertices and six linesegments.Using the ArcMap Integrate commandThe ArcMap Integrate command joins together, or integrates, all feature classes in a shapefile or feature dataset. It works on the premise that there are features in your data that have a distance between them that need to be snapped together for the data to make sense. Integrate is different from the ARC CLEAN command, which is available in ArcInfo Workstation. It does not merge features; it only makes them coincident. Also, it does not create topological relationships. Integrate does not work on ArcInfo coverages.Here, features become coincident but remain as separatefeatures.When using Integrate, you can set the distance that features will be snapped together. This distance is called the cluster tolerance. The cluster tolerance is the distance range in which all points are considered one. For example, if the cluster tolerance is set to 10 map units, after running Integrate, vertices within 10 map units from each other will become coincident. You should set the cluster tolerance as low as possible to avoid error.Integrate gives you two options: you can integrate either the visible or the full extent of your data. If you integrate only the visible extent, only the features within the area displayed on the screen will be integrated.The Editing Options dialog gives you options for the extent you want to integrateand how close you want vertices to be.ExerciseEdit features with the Editor toolbarIn this exercise, you will modify an existing parcels basemap. You will learn how to use some of the tools available on the Editor toolbar and get a feel for how easy it is to edit features in ArcMap.Estimated time to complete: 15 minutesStep 1Start ArcMap and load the dataStart ArcMap and open a new map document. Click the Add Data button and navigate to yourLearnArcGIS1¥workdata¥Lesson02 folder. Double-click Subdivision.mdb, then clickSubdivisionParcels. Click Add.The SubdivisionParcels layer contains eight parcels.Step 2 Open the Editor toolbar and start an edit sessionBefore you can start an edit session, you must display the Editor toolbar. If it's not currently displayed,click the Editing button on your Standard toolbar to add the Editor toolbar.If you like, dock the toolbar somewhere else on your ArcMap window or undock it so that it's floating onyour desktop.Notice that most of the buttons, menus, and dropdown lists on the Editor toolbar are disabled. This is because you haven't started an edit session.From the Editor menu on the Editor toolbar, choose Start Editing.The buttons, menus, and dropdown lists are now enabled.Step 3 Select and move a parcelFirst, you will use the Edit button. The Edit button is the primary tool for selecting and moving features and manipulating vertices.(it may already be active). Click on the parcel in the northeast corner.Click the Edit buttonThe parcel is highlighted and your mouse pointer changes to indicate that you can drag the feature.Notice that several buttons are now enabled on the Editor toolbar.Drag the selected parcel to the right so that it's no longer connected to the other parcels.Note: If you drag the parcel outside the map extent, follow these steps: from the View menu, choose Zoom Data, then Fixed Zoom Out until you can see the feature.Step 4 Rotate a featureNext, you will rotate the selected parcel. The parcel will rotate around its selection anchor (the blue 'X' in the center of the parcel). If you docked the Editor toolbar, you may have to enlarge the ArcMap windowto see the Rotate button.Click the Rotate button .Click and drag anywhere in the display to rotate the feature around its selection anchor.Step 5 Move the feature's selection anchorYou can move the selection anchor to see how the anchor affects the rotation of the feature.Hold your mouse pointer over the selection anchor until the pointer icon changes. Click and drag the selection anchor to a new location outside of the feature, slightly down and to the left. Rotate the parcelagain.Step 6 Specify a rotation angleYou can also rotate a feature by specifying an angle. The angle is relative to the feature being rotated and is specified in degrees. A positive angle rotates the feature clockwise; a negative angle rotates the feature counterclockwise.and press Enter to rotate the feature 45 degrees clockwise.Press A on your keyboard. Type 45Step 7 Move a vertexYou can use the Edit button to move a vertex.Click the Edit button and double-click the parcel that you've been editing.The parcel's sketch appears to show you the location of its vertices and segments.Move your mouse pointer over the bottom vertex. Drag the vertex to a new location.The lines showing the new shape are part of the sketch.Step 8 Delete a vertexYou can modify vertices quickly using the context menu that appears when you right-click a sketch.Move your mouse pointer over the upper-left vertex. Right-click to access the Sketch context menu.Click Delete Vertex.f yours is different, that's OK.Your sketch should resemble the one below擁Step 9 Add a vertexIn addition to moving and deleting vertices, you can add vertices.Move your mouse pointer over the bottom line of the sketch. Right-click to open the Sketch contextmenu and choose Insert Vertex.Click anywhere away from the sketch to finish editing its vertices.Step 10 Delete the parcelSelect the parcel by clicking it. On the Standard toolbar, click the Delete button or press Delete on your keyboard.The parcel is deleted.Step 11 Save changes and exit ArcMapFrom the Editor menu, choose Stop Editing. Click Yes when prompted to save changes. From the Filemenu, choose Exit. Click No when prompted to save the map document.Lesson summaryIn ArcMap, you can edit spatial and attribute data for geodatabases, coverages, and shapefiles. When you want to edit data, you start an editing session and specify the workspace that contains the data you want to edit. ArcMap provides many tools for editing data, many of which are available from the Editor toolbar. You can also copy/paste features across layers, delete features, and undo and redo changes using buttons on the Standard toolbar.The ArcMap Integrate command creates coincident geometry in a feature dataset or shapefile. In ArcMap, Integrate does not merge features or create topological relationships; it merely makes features coincident. Integrate allows you to specify feature snapping distance, also called the cluster tolerance. You can integrate either the visible extent or the full extent of your data.A sketch is a shape that represents a feature's geometry. A sketch consists of vertices and segments; points do not have sketches because they don't have vertices or segments. When you want to create a new feature, you create a new sketch. When you want to edit a feature, you work with its sketch. The Sketch context menu contains the tools you need to work with sketches.Lesson self testThis is the Working with Spatial Data in ArcGIS - Lesson 2 Self test.Please watch your time—you have 2 hours to complete this test.Use the knowledge you have gained in Working with Spatial Data in ArcGIS to answer the following questions. You will need to correctly answer 7 of the following questions to pass.GOOD LUCK!1.To edit a feature, you work with its sketch.TrueFalse2. A sketch represents a feature's geometry.TrueFalse3.If you are editing data stored in two different geodatabases, you must specify which data you want to edit.TrueFalse4.The Edit tool selects and moves features from what layer in ArcMap?Only the layer listed first in the Table of ContentsOnly layers that are highlighted in the Table of ContentsLayers specified as selectableAll layers5.The selection anchor is the point where you click to select a feature.TrueFalse6.For which tasks can you use the tools on the Standard toolbar?Pan and zoom around the dataSelect and move features in the layers that are selectableStart and stop an edit sessionCut or copy and paste features across layers7.If you have two layers named Zoning and Parcels that are stored in the Subdivision geodatabase, and youhave another layer called Sewer that is stored in the Utilities geodatabase, which statement below is true?You can edit either the Sewer layer or both the Zoning and Parcels layers, but not all three in one edit session.You can edit all three layers in one edit session.You can edit only one layer during an edit session.You have to tell ArcMap which layer you want to edit.8.Which of the following is not a method for specifying a rotation angle?Select the feature, click the Rotate button on the Edit toolbar and then position the pointer over a vertex to rotate the feature on its anchor point.Right-click with the Sketch tool and choose Angle/Length from the context menu.From the Insert menu, choose Angle and type the angle into the box.Right-click with the Sketch tool and choose Angle from the context menu.9.If you use the ArcMap Integrate command to integrate the visible extent, what happens?Coincident geometry is created for the data visible in your map.Coincident geometry is created for the entire dataset.The map is clipped to the visible extent.The entire dataset is integrated.10.When you first display the Editor toolbar, why are all the buttons disabled?You haven't started an edit session.You haven't selected any features.You haven't specified the edit feature.You haven't specified the target layer.。