Editing Features
Before tackling this tutorial, you will need to download and install a dataset following these instructions:
Create a folder called Editing_basics somewhere under your personal directory (e.g. C:\Users\jdoe\Documents\Tutorials\Editing_basics\).
Download the data for this exercise then extract the contents of editing_basics .zip into your newly created Editing_basics folder.
Open the map document
Navigate to your Editing_basics folder and double-click the editing basics.aprx file.
The map covers the Colby campus and consists of two layers: an incomplete roads polyline layer and an east boundary polygon layer.
A few tips that might help improve your experience editing features in ArcGIS Pro:
If you want to undo an edit, use the Ctrl + Z shortcut key.
Restrict the editable layer to that being edited (this step is shown in the Digitizing a new polygon section).
Be mindful of the feature that is selected. You can always clear a selection by clicking on the Clear button in the Edit ribbon.
Save your edits to the GIS data file on a regular basis. This avoids having to start an edit session from scratch if ArcGIS crashes.
Read through the instructions first before starting an editing exercise. Each editing exercise is capped with a short video recap of the steps. You might want to view the video before tackling the edit session.
Creating a new polygon feature shapefile
Your first task will be to digitize Johnson Pond. Before you begin your first digitization task, you will need to create a new polygon shapefile.
To the right of the data view window, click on the Catalog tab.
In the Catalog pane , right-click on the editing_basics folder connection and select New >> Shapefile.
In the Create Feature Class pane, name the new feature JohnsonPond (make sure not to add spaces in the name).
Select Polygon as the Geometry Type.
Adopt the same coordinate system as that of the Current Map. Alternatively, you could select the new layer's coordinate system via the globe icon to the right of the field (then, navigating to Projected Coordinate System > UTM > NAD 1983 > NAD 1983 UTM Zone 19N).
Click Run to create the new shapefile.
You just created a new (empty) polygon shapefile. The layer should be automatically added to your Contents pane. If not, add the layer manually to the Contents pane via the Catalog pane.
The JohnsonPond layer is currently empty. In the next step, you will add a new polygon feature to that layer.
Adding an aerial imagery backdrop
In this exercise, we will use aerial imagery of the campus as a backdrop to delineate the features of interest. Imagery can be loaded as separate raster file layers, or as aerial imagery streamed across the web via ESRI's image services (a service freely available in ArcGIS Pro). Here, we'll opt for the latter option.
In the Map ribbon, click on Basemap and select Imagery.
This will add a World Imagery layer to the Contents pane. Note that the imagery changes over the years, so your imagery may be updated from the one shown in this exercise.
Digitizing a new polygon feature
In the Bookmarks pull-down menu from the Map tab, select Johnson pond.
Your map extent should now encompass Johnson Pond.
Before we start digitizing, we will set the JohnsonPond layer’s transparency to 50%. This will be helpful in seeing the underlying pond.
With the JohnsonPond layer selected, click on the Feature Layer tab.
Set the transparency to 50 %.
Next, we'll start the edit session.
Click on the Edit tab. This will bring up the Edit ribbon.
Since we will create a new polygon, we will select Create.
When you start an edit session, a Create Features pane pops up on the right-hand side. The Create Features window lists all editable layers, and displays the corresponding map symbol next to each layer. These are known as feature templates.
If you have multiple editable layers in your map document, you might, at times, inadvertently edit the wrong layer. It's good practice to explicitly restrict the edit session to the layer whose features are being edited/created. We'll do this next.
In the Contents pane, select the List by Editing view (this is the pencil icon).
Uncheck all vector layers except JohnsonPond.
Note the exclamation mark next to the World Imagery layer. This just indicates that the imagery layer is not editable.
After unchecking the vector layers, you should only see the JohnsonPond layer in the Create Features pane.
Click on the JohnsonPond layer in the Create Features pane.
A list of construction tools will appear under the layer. The choice of construction tool used will depend on the type of editing you will perform.
Select the first icon (Polygon) from the construction toolset.
You are now in edit mode. The editing steps consist of digitizing the feature of interest (pond in this example) by creating vertices (via the left mouse button) along the features' edge. When you've completed the delineation of the feature, you'll exit the edit. The step-by-step instructions are shown next. A short video (with no audio) showing the steps is also shown at the end of this section (you might want to view the video before starting the edit session).
With your left-mouse button, create vertices that will define the edges of the pond. The spacing of the vertices should be defined by the desired level of resolution.
To delete the most recent vertex, you can click on the Ctrl + Z keys to undo the last vertex.
Roll the middle mouse button to zoom in and out.
Click and hold the middle mouse button to pan around the map as you digitize.
When you are done delineating the polygon feature, you exit the current edit by either pressing the F2 key on your keyboard, or by clicking on the Finish button in the Tool palette at the bottom of the view window.
Here's a video of a sample edit session. Note that the video is muted.
The polygon we just created only persists in our current map session. In other words, if we were to close ArcGIS Pro, we would lose that edit.
To permanently save the edit to the shapefile, navigate to the Edit tool and click on Save.
If the Save button is ghosted out, you either already saved the changes or you did not complete the polygon edit.
Editing an existing polygon
So far, you've learned how to create new, isolated, polygons. When appending to an existing polygon, or modifying the inside boundaries of a polygon, different editing tools should be used. A few examples follow.
Appending to an existing polygon
In this section, you will learn how to properly append a polygon to an existing polygon. You may be tempted to use the Polygon tool from the previous section, however, this would require that you delineate the entire polygon, including boundaries shared with an existing polygon. While this process is allowed by ArcGIS, it risks creating gaps and overlaps along the shared boundary. Instead, you will use another editing tool: the Autocomplete Polygon tool.
In the next step, you will append the quad area to the East Boundary layer.
From the Bookmarks pull-down menu, select Quad.
This should place the map's extent over Colby's quad.
In the Contents pane, make the East boundary layer editable and unselect JohnsonPond.
From the Edit tab, select Create.
This will bring up the Create Features pane (if it's not already open). You'll note that the East boundary layer is now the only editable layer in the pane.
Click on the East boundary layer to reveal the editing tool choices.
Select the Autocomplete Polygon tool.
To use this tool, you start by clicking anywhere inside of the existing polygon you are appending the new polygon to. Where you click does not matter since this first click will not generate a permanent vertex. Your next click will be on the boundary where you want one end of the shared boundaries to be recorded. You then delineate the area of interest as you did with Johnson pond. The last vertex will be placed on the other end of the shared boundary. You can then choose to finish off the polygon by double-clicking anywhere inside the existing polygon, ore pressing the F2 key, or clicking the Finish button. An example of the aforementioned steps is highlighted next. A video demonstration is also shown at the end of these steps.
Click somewhere inside the existing East boundary polygon.
Click along the edge of the polygon where you want one end of the shared boundary to start.
You'll note that ArcGIS will help snap your point to the existinging polygon edge. This will be indicated by the East boundary: Vertex helper pop-up label in the View window.
At this point, you can delineate the western end of the quad. This should consist of two vertices that define the quad's western corners.
Snap the last vertex to the existing polygon's edge where the upper end of the shared boundary should end.
To finish editing the appended polygon, double-click anywhere inside of the existing polygon. Alternatively, you can press the F2 key or click the Finish button.
Your polygon should now be complete. Note how ArcGIS automatically closed off the eastern end of the polygon by automatically creating the vertices needed to generate a perfectly shared boundary devoid of gaps and overlaps.
To ensure that the changes are permanent, click on the Save button to save the changes to the shapefile.
Here's a video of a sample edit session. Note that the video is muted.
Carving out a polygon inside of an existing polygon
Another kind of editing procedure involves carving out a polygon inside of an existing polygon. The choice of editing workflow will matter. For example, when using the Polygon editing tool to create a polygon inside of an existing polygon, you will end up having two representations for the same area. In other words, the new polygon will overlap the existing polygon (first example in the following figure). If you clip out the underlying polygon with the newly created one, you end up with a single representation of that same area (second example in the following figure). Since we don't want the same area represented twice, we'll opt for the second option in the example that follows.
Next, we will delineate the Colby Green inside of the East boundary polygon.
From the Bookmarks pull-down menu, select Colby Green.
This should place the map's extent over Colby's Green oval.
In the Create Features pane, Select the Polygon tool.
Digitize the outline of the Colby Green in the same way you digitized the outline of Johnson pond.
When done, click either the F2 key or the Finish button from the edit toolbar at the bottom of the Map window.
Next, we'll clip out the area shared by both polygons.
Make sure that the polygon you just created is selected. If it's not, use the Select tool found in the Edit ribbon and select the polygon. In doing so, you will probably see a small square window pop-up indicating that you have more than one polygon at the location you just clicked. If so, click on the small arrow on the right-side of the square pop-up window and select the second entry (this is the polygon you just created). Note that the polygon number shown in the figure may not match that in your edit session.
With the polygon selected, expand the Tools window in the Edit ribbon.
From the list of options, select the Clip tool.
This will bring up a Modify Features window pane.
Make sure that Discard is selected (this will remove all features sharing the same area as the polygon you have selected).
Make sure that Clip all editable features is checked. (Note that this is one reason you want to restrict which layer is being edited).
Click Clip.
You can tell that the underlying polygon was clipped and discarded by selecting the Colby green polygon with the Selection tool. If you do not see the little pop-up window at the location you clicked, then there are no overlapping polygons. If you still see that little pop-up window, then you did not properly clip the polygon as outlined in the last step.
At this point, it's probably a good idea to save the changes to the layer. Recall that edits only persist in memory until they are explicitly saved to the shapefile.
Splitting a polygon
In this next exercise, you will learn how to split an existing polygon. You will delineate the wooded section of the East boundary layer which will end up splitting the polygon into two sections. The steps are outlined below.
Zoom out to the full extent of the East Boundary layer.
Next, you will split the polygon into two parts by digitizing the boundary separating the wooded area from the developed area.
Select the large polygon (you do not need to select the Colby green or west quad polygons).
In the Edit ribbon, expand the Tools window and select the Split tool.
Zoom in near the bottom of the boundary.
Click anywhere outside of the polygon to initialize the edit. This first clicked location will not be saved as a vertex.
Click at the location where you want to start the polygon split (this will be at the boundary between the grassy area and the wooded area). Take advantage of the auto-snap feature (You'll know that it's snapping when the East boundary: Vertex helper text pops up).
Begin the digitizing process until you reach the wooded/grassy area boundary near the upper end of the East boundary polygon.
Roll the middle mouse button to zoom in and out.
Click and hold the middle mouse button to pan around the map as you digitize.
The last vertex will need to be placed on the existing polygon's boundary. You can take advantage of the snapping feature to ensure that the vertex is placed along the polygon boundary.
To finish the edit, double-click anywhere outside of the polygon.
Save your edits.
You now have to separate polygons. Note that they do not overlap.
Here's a video of a sample edit session.
The background image used in the video will very likely not reflect the updated version of the imagery on your PC.
Editing attribute tables
When adding features to a vector layer, you probably want to edit their attributes. You can do so via the layer's attribute table.
Right-click on the East Boundary layer and select Attribute Table to open its attributes table.
You'll note a few things. First, the west quad polygon and the colby green polygon have an empty Name field--this is to be expected given that these were newly created polygons. Second, the East boundary value appears twice in the table. This is a result of the original polygon being split into two which leads to attribute value(s) being shared across the split polygon.
You can edit the table as you would a spreadsheet.
Assign the values to the Name column as shown in the following figure.
Note that you can identify the polygons associated with each record by selecting the row of interest.
When you are done editing the attribute table, you need to save the edits (Edit tab >> Save).
Editing line features
In the exercises that follow, you will be exposed to a few line editing tools and workflows.
Adding vertices to lines
In the following steps, you will reshape Mayflower Hill drive by adding/moving vertices along the line segment.
In the Contents pane, make the Roads layer editable. Be sure to uncheck any other layers in the List by Editing view.
You might also want to turn off the East boundary layer from you map view. This will make it easier to view the underlying imagery when editing the Roads feature.
Zoom in on the stretch of road near the Colby green. Note how it does not hug the road feature in the imagery. This portion of the road segment will need to be edited.
Select the line feature representing Mayflower Hill drive .
From the Edit ribbon, select the Edit Vertices tool.
This will display the vertices that define each line segment of the Roads polyline feature.
Right-click anywhere on the line segement whose path you want to modify, and select Add Vertex.
You don't have to worry about placing the vertex exactly since you will move it in the next step.
Left-click on the newly created vertex and move it to a location along Mayflower Hill drive.
Add a few more vertices to the line segment and move them to the road centerline following instruction outlined in the previous two steps.
Now that you've reshaped the line segment, press the F2 key or click on the Finish button to accept the changes made to the line segment.
Here's a video of a sample edit session. Note that the video is muted.
Adding line segments
In this next exercise we will all a polyline that will connect the Lunder/Diamond parking lot to the Alumni/Davis parking lot.
If the Create Features pane is not already active, click on the Create button in the Edit toolbar.
In the Create Features pane, select the Line tool
Next, digitize a new polyline connecting the two parking lots. Make sure that the starting and ending vertices snap to the existing polyline features in the layer.
When done digitizing, press the F2 key or click on the Finish button in the editing toolbar.
Here's a video of a sample edit session.
Note that the background image in the video may differ from the one on your screen.
Extending line segments
In this next exercise, you will learn how to extend and snap existing line segments to another existing line. While this can be done by dragging the end vertex to a snap point on the adjacent line, you will learn how to leverage the Extend/Trim tool to accomplish this task more effectively.
From the Tools pulldown menu in the Edit ribbon, select the Extend or Trim tool.
To the south of the Diamond building, select the feature whose dangling line you want to extend.
This will open the Extend or Trim window pane on the right-side of your map display.
In the Extend or Trim window pane, select the Extend option.
Hover the cursor over the line representing Mayflower Hill drive. In doing so, you will see a grey line extending from the selected line feature to the Mayflower Hill drive line segment. This is a preview of what will happen if you click on the current cursor location.
Click on where the cursor is hovering to accept the proposed extension.
The selected polyline should now be extended to the adjacent line.
Repeat the same steps to extend the Davis/alumni drive to Mayflower Hill drive.
Here's a video of a sample edit session. Note that the video is muted.
At this point, it's a good idea to save your edits to the shapefile by clicking on the Save button in the Edit ribbon.
On your own, feel free to continue editing the layers, or adding new ones as needed using the backdrop image as reference. Don't forget that you can always undo edits using the Ctrl + Z shortcut key and you can unselect features by clicking the Clear button in the Edit toolbar.