Lab 2: Building a Geodatabase, Creating Features, and ...



1 Lab 2. Creating and Editing Features

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2 Introduction

This lab introduces how to create and edit spatial features and their attributes in ArcGIS.  You will learn the following skills:

▪ Create and modify features

▪ Work with and create feature templates

▪ Work with editing tools and toolbars

▪ Edit feature attribute values

▪ Use the Field Calculator tool

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4 Instructions

Based on the assigned readings for this week, answer questions in Part I of this lab. Then proceed to Parts II & III to complete hands-on exercises. Before working with the lab data, download it from the course website and save onto your flash drive.

5 Deliverables

Answer the questions marked in bold and produce the required outputs. Your lab document should be typed, well organized, and submitted according to the course “How To” guidelines.

PART I: Assigned Readings

Textbook – Bolstad (Chap. 4, pgs. 140-156)

1. What are two advantages of on-screen digitizing over hardcopy/scan digitizing?

2. Why would it be inappropriate to digitize a dot-density map as a point dataset?

3. What happens to map errors as the map scale becomes smaller?

4. Describe the difference between digitizing in “point mode” vs. “stream mode”.

5. How does snapping improve editing or digitizing?

6. In the context of scan digitizing, what is “skeletonizing”?

7. When editing geographic data, what are two methods to identify data errors?

ESRI ArcGIS 10 Online Help Files

8. What is the basic workflow for editing data in ArcMap?

9. What are two ways to start an edit session in ArcMap?

10. What are the two windows that you can use for editing attributes?

PART II: Editing In ArcGIS Desktop 10.1

The exercises you will complete in this section are modified from the online ESRI training module – Editing in ArcGIS Desktop 10. I have updated the materials to reflect some changes in version 10.1.

The exercise is focused on learning new editing tools by completing a variety of different tasks in and around a subdivision called Miller’s Ranch.

• Download the Lab2Data from the course website and unzip the file.

• In the Lab2Data (Part II) folder, open MillersRanch.mxd

• If necessary, change the scale to 1:2500.

The map shows a rural area just outside Manhattan, Kansas. It is currently centered over a lake located within Anneberg Park. In the table of contents, notice that two raster layers are currently displayed, while the city’s water systems, streets, and parcel layers are turned off.

• Turn on the Editor toolbar. You can do this on the standard toolbar and click on ‘Editor Toolbar’

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• Once the Editor toolbar appears, go to the ‘Editor’ dropdown menu and click on ‘start editing’

• The Start Editing dialog box opens. This is where you specify what layer you want to edit. Click on the Lakes layer to highlight it.

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• The pencil icon should now display next to the Lakes layer in the top pane and next to the path for the Planning.gdb layer in the lower pane (where the Lake layer is stored)

• Click OK

• The Create Features window should open and will list all the editable layers, as well as the corresponding map symbol next to each layer. These are known as feature templates.

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• In the Create Features window, click on the Lakes layer. This should make several construction tools appear on the lower portion of the Create Features window.

• Click on the Polygon tool (in the construction tools) and move the cursor into the map area. Click anywhere along the shoreline of the lake to add your first point.

• Continue digitizing the lake’s shorelines by click your mouse to add more vertices. When you are finished, right-click and choose Finish Sketch. Alternatively, you can double-click to finish your sketch or press F2 on your keyboard.

1. Take a screenshot of your map in data view with the newly created polygon and insert it into your lab document.

• Now, you will update the Name attribute for the lake feature. On the Editor Toolbar, click the Attribute button.

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• The Attributes window appears, docked in the same position as the Create Features window. In the Attribute window, right-click Lakes and open the layer properties for the Lakes layer.

• Click on the Display tab.

• Set the Field for the Display Expression to NAME and then click OK.

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• In the Attributes window, for Name type in Anneberg Lake and press Enter.

• On the Editor Toolbar, go to the Editor dropdown menu and click Save Edits.

2. Take a screenshot of the Attributes Window so I can see the name change and insert into your lab document.

• At the bottom of the Attributes window, you should see a table to toggle back to the Create Features window. Click on the Create Features tab.

• Click on the Organize Templates button in the top left corner.

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• In the Organize Templates dialog box, you can create new feature templates and make changes to existing ones. Click on Properties.

• In the lower portion of the dialog box, click next to the NAME attribute and type, Irrigation Pond, and press Enter.

• For the default tool, click the dropdown arrow and choose Freehand tool.

• Click OK.

• From the Bookmarks menu, choose Irrigation Pond.

• In the Create Features window, click the Lakes feature template. Notice that the Freehand tool is automatically selected in the bottom pane because you specified it as the default construction tool for the Lakes template.

• Move your mouse over the map area and click once on the upper-left corner of the irrigation pond.

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• Move your mouse without clicking around the pond’s shoreline, going South from the upper-left corner, around the bottom, and north up to the upper-right corner.

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• When you finish your line at the upper-right corner of the irrigation pond, the final segment is drawn between your start and end points.

• Save your edits.

3. Take a screenshot of the newly drawn Irrigation Pond and insert into your lab document.

• Next, you will edit new streets for a new subdivision known as Miller’s Ranch.

• Go to the Bookmark menu and click on Miller’s Ranch North.

• Turn on the Streets & Parcel layers. Turn off the Irrigation Pond & Anneberg Lake layers.

• At the top of the subdivision, notice the gap between the roads.

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• You will fix this gap by modifying the vertices of the road centerline. Right-click the Streets layer and choose Edit Features>Start Editing.

• Next, we will set the Snapping options. Snapping moves points or vertices to coincide exactly with the vertices, edges or end points of other features. Go to Customize>Toolbars>Snapping.

• Go to the Snapping dropdown menu and go to Options.

• Under the Snapping options dialog box, enter a Tolerance of 5 pixels.

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• Click Ok.

• Click on the Edit tool (on the Editing Toolbar).

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• Select the street centerline located on the west side of the Miller’s Ranch subdivision, shown below.

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• Right-click the selected centerline and choose Edit Vertices.

• The vertices along the line should appear and the Edit Vertices toolbar will automatically appear.

• On the Snapping Toolbar, shut off all snapping agents (the four buttons to the left of the dropdown menu) EXCEPT Vertex snapping.

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• Go back to the street centerline you have highlighted and hover your mouse over the northern-most vertex until it changes to a hollow diamond shape.

• Click and drag the vertex, snapping to the street’s vertex.

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• On the Edit Vertices toolbar, click on the Finish Sketch button.

• Save your edits.

4. Take a screenshot of the newly connected subdivision street and insert into your lab document.

• Now, we are going to use some editing tools that allow you to ‘trim’ and ‘extend’ line features. Go to the Bookmarks menu and click on Extend/Trim.

• Notice that some of the streets extend too far or are digitized too short to intersect the main centerline. You are going to fix these.

• Hold down the Shift key as you select the three roads that need to be extended, as shown below.

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• Zoom in to one of the selected streets so you can measure the distance that it needs to be extended.

• On the Snapping toolbar, turn on Edge Snapping.

• One the Tools toolbar, click the Measure Tool.

5. What is the gap distance between the centerline and each of the three streets?

• Go back to the Extend/Trim bookmark.

• Go to the Search window and type in Extend Line and click on it when the search results appear.

• The Extend Line tool opens. For Input Features, click the down arrow and choose streets. For Extend Length (optional), enter 40 feet. (Since you have the 3 lines selected, the tool will only work on the selected features). Click OK.

• The three streets should now extend to the main road.

• Near the center of the map, locate the street that is too long and needs to be trimmed. Click this street to select it.

• Use the Measure tool, determine the dangle length (length that it needs to be trimmed).

6. What is the dangle length?

• In the Search window, search for and open the Trim Line tool.

• Trim the features using the Streets layer and your pre-determined dangle length (your trim distance needs to be at least as long as your measurements). Click ok.

• Save your edits.

7. Take a screenshot of the extended/trimmed streets and insert into your lab document.

• Now, we will change straight lines into curved or Beizer curves. You can also change a curved segment to be straight.

• Go to the Bookmarks menu and click on Persimmon Circle. Persimmon Circle is the street in the center of your map.

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• With the Modify Sketch Vertices tool, double-click Persimmon Circle to display the vertices.

• Drag a box around the three middle vertices to select them all.

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• Right-click one of the selected vertices and choose Delete Vertex.

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• Click the Finish Sketch button (Edit Vertices toolbar). The street should now only be a two-part line.

• Double-click Persimmon Circle to select it, then right-click and choose Change Segment > Beizer. A beizer curve is distributed across the segment, as shown below.

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• Experiment moving the handles to see the effect on the curve as they are moved. Adjust the handles as needed to make Persimmon Circle a smooth curve that is centered within the road right-of-way.

• Save your edits and stop editing (On the Editing oolbar, go to the Editor dropdown menu and click on Stop Editing).

8. Take a screenshot of Persimmon Circle with the new Beizer curve and insert into your lab document.

• The next step is to update the city boundary to include the new Miller’s Ranch subdivision, which was recently annexed. You will then use the updated line features to create a polygon for the map.

• Open the ArcCatalog tab (within ArcMap) and expand the Lab2Data folder (Part II) and the Planning Geodatabase within it.

• Drag the City_Boundary feature class into your map.

• Change the symbol for the City_Boundary layer to a width of 2.

• Zoom to the extent of the City_boundary layer (right click on the layer in the TOC and go to Zoom to Layer).

• Turn off the Streets layer.

• Open the City_Boundary attribute table. You should see two lines – the original city boundary line and a new line, which includes the recently annexed Miller’s Ranch subdivision.

• Select each feature to view it on the map. In the next few steps, you will merge these features into one to represent the updated city boundary. Close the table.

• In order to prevent parcels being selected during this editing session, click on the List by Selection tab in the TOC (table of contents).

• Make the Parcel layer ‘Not Selectable’

• Go back to List by Drawing order.

• Start an editing session for the City_Boundary layer. The create features window should appear with a feature template for the city boundary. If this does not happen for some reason, go to Manage Template and create one.

• Right-click on the City_Boundary layer and choose Selection > Select All.

• From the Editor dropdown menu (Edit toolbar), select Merge.

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• The two features are listed in the Merge dialog box. Click OK to merge the lines into a single line feature and then save your edits.

• Now, you will create a new polygon of the updated city boundary.

• Drag the City_Area feature class into your map (Planning geodatabase) and create a Feature Template for the layer.

• Go to the Customize menu and choose Toolbars > Advanced Editing.

• On the Advanced Editing toolbar, click the Construct Polygons tool [pic].

• Make sure that the City_Area feature template is highlighted.

• Enter 0.5 for the Cluster Tolerance and click OK.

• A new polygon should appear! It is now in the City_area layer and was constructed from the City_Boundary line geometry.

• Clear your selection and save your edits.

9. Take a screenshot of the City_Area polygon and insert into your lab document.

• Next, you will create a new water line for the subdivision using a new tool to create your pipe parallel to the north parcel boundary.

• Turn off City_Area & City_Boundary and turn on Pipes & Streets.

• Go to the Catalpa Circle bookmark. Catalpa Circle is the small cul-de-sac near the center of your map.

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• Start an editing session for the Pipes layer.

• In the Create Features window, right-click the Pipes feature template and choose Properties.

• In the Properties, Set the Line_diameter to 4 and Line_Type to Lateral. This will change the defaults for any new features being added.

• Set snapping to Vertex & Edge snapping.

• Make sure the Pipes feature template is selected.

• Snap your cursor to the existing pipe vertex located just north of Catalapa Circle centerline, as shown below.

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• Click the Vertex to enter the first point of your new water line.

• On the Feature Construction toolbar, click on the Constrain Parallel tool [pic], then click the parcel edge as show below.

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• Move your cursor and notice that your sketch remains parallel to the parcel edge. Right-click and choose Length.

• Enter 125, press Enter and finish your sketch.

10. There is more than one way to finish your sketch. List at least two of these ways.

• Open the Attributes Window from the Editor toolbar and notice that the Line_diameter and Line_type are set to the default values.

• For the Install_Date click on the value and click on the down arrow. Choose today’s date.

• Clear your selection and save your edits.

11. Take a screenshot of the new pipeline in Catalpa Circle and insert into your lab document.

• The last thing you will do is move a hydrant that has been relocated. Turn on the Hydrants layer.

• With the Edit tool, select the Hydrant feature.

• With the Edit tool, move the hydrant to the junction of the new water line that you added above.

• Save your edits and stop editing.

12. Take a screenshot of the moved hydrant in Catalpa Circle and insert into your lab document.

PART III: Digitizing from an Aerial Photo

Problem Statement / Background:

You are working for the City of Portland and in charge of digitizing aerial photos to create GIS datasets of roads, buildings, and parks in Portland. Using the aerial photo image in the Lab2 data folder, you will create a new geodatabase and three features classes (roads, bldgs, parks).

**Be sure to save your edits often while working!!!!

▪ Start by creating a new Personal Geodatabase in ArcCatalog.

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▪ Within the geodatabase, create a new feature dataset named “Portland”. Choose the same projected coordinate system as the aerial photo image (NAD_1983_UTM_Zone_10N), and for the vertical coordinate system. Accept the default tolerance values, resolution and domain extent. Note that you set the projection for all the feature classes when you create the feature dataset.

▪ In the feature dataset, add a new feature class named “Buildings” that contains Point features. Add a new field named “type” and of Data Type “Text”. Click the Finish button to create the feature class and close the New Feature Class window.

▪ Create two additional feature classes: Parks (polygon) and Streets (line). No additional attributes are necessary for these two datasets.

▪ You need to make sure that your streets do not have any “dangles” (i.e. lines that hang over other lines). To prevent this, you are going to create a new topology layer.

▪ Right-click on the Portland feature dataset and go to New > Topology.

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▪ Go through the New Topology wizard and create a new topology layer for the Streets feature class. Name it “Portland_Topology” and use the rule called “must not have dangles”.

▪ Open a new .MXD document. Add the aerial photo image (“Neighborhood.tif”) from the Lab2Data (Part III) folder, the three new feature classes and the new topology layer. Make sure that the aerial photo image displays below all of the other layers.

▪ Start an editing session.

▪ By default, all snapping types are turned “on” (i.e. activated). For the sake of comparison, let’s start by creating features without using snapping.

▪ Go to the Customize menu > Toolbars > Snapping to activate the Snapping toolbar. Note that all of the snapping types (Point, End, Vertex and Edge) are highlighted, which means they are active. Click on each snapping type to turn them all “off”.

▪ Now let’s create some new street line features. Within the Create Features editor window, first select the “Streets” layer, then select a tool from the Construction Tools section.

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▪ Sketch several streets, and then check your topology.

▪ Add the Topology toolbar to ArcMap by going to Customize > Toolbars > Topology.

Click on the Validate Topology in Current Extent tool on the Topology toolbar. If any streets within the specified area contain dangles, then a small box will display at each dangle location.

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Validate Topology in Current Extent

▪ To correct the dangles, zoom in and use the Extend and Trim tools, which are found in ArcToolbox and on the Advanced Editing toolbar (go to Customize > Toolbars > Advanced Editing). Recall how to use these tools from the exercises that you completed for Part II of this lab.

▪ Now let’s improve your digitizing experience. On the Snapping toolbar, turn “on” the snapping function for vertices, edges, and ends.

▪ Continue sketching the remaining streets and validate the topology again.

1. Do you have any topology errors after turning on the snapping function?

▪ Using the Construction tools, digitize the park and building features on the image. Note: when you are creating the building features, be sure to enter in a “type” value (“commercial” or “residential”) for each one. Use the Attribute Table editing tool on the Editor toolbar (highlighted with a black box below).

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▪ After digitizing all three data sets, go to the Editor toolbar > Stop Editing to close out the editing session. Be sure to save all of your edits!

▪ Open the attribute table for the Parks feature class. You will see an “Area” attribute that has been automatically added (this is true for all feature classes within a geodatabase). The area units are most likely in square meters (because UTM is in meters). However, you’d like to know the area in acres. Let’s add a new field to the attribute table and calculate area in acres into the field.

▪ To add a new field to the attribute table, click on the Table Options button and select the Add Field… option.

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▪ Name the new field “acres” and set it to Type “Double” (which allows it to contain decimal values).

▪ Right-click on the “acres” field and select the Calculate Geometry option. Within the Calculate Geometry window, calculate the area in acres.

2. How many acres is the park in the map (approximately)?

3. When you are finished, create two maps (alternatively, you can choose to have one map with two data frames)- one with the aerial photo and one without. Both should have the three new datasets. Symbolize appropriately and add all necessary map elements for a presentation quality map. Symbolize the commercial and residential buildings differently. Export your map(s) as a .JPG and insert into your lab document along with your responses.

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