In this lesson, you'll process large general datasets to remove unnecessary information and focus only within your geographic area of interest. To do this you'll download global boundary files from the ArcGIS Living Atlas of the World, remove all features not related to the Democratic Republic of the Congo, and merge multifeature polygons into single features. The boundary files will serve as reference data needed to analyze and visualize population and malaria incidence in the next lessons.
Add and extract boundary data from the Living Atlas
The Living Atlas serves as a continuously updated and authoritative source for data. In this section, you'll add global boundary data from the Living Atlas and extract relevant country features. The extracted features will later be appended with population and malaria incidence data to calculate incidence rate and visualize.
- Start ArcGIS Pro. If prompted, sign in using your licensed ArcGIS or Enterprise Account.
If you don't have ArcGIS Pro, you can sign up for an ArcGIS free trial. If you are signing into an Enterprise account ensure that ArcGIS Pro is configured to use your organization's Portal.
ArcGIS Pro opens. It contains a list of project templates under the heading New. If you've created a project before you'll also see a list of recent projects under the heading Recent Project.
- Under New, click Map.
- In the Create a New Project window, change the project name to MalariaEpidemics. Click OK.
A new project opens with a Contents pane on the left and a map pane in the center.
Now you'll add boundary data from the Living Atlas.
- On the ribbon, click the Map tab. In the Layer group, click Add Data.
The Add Data window opens. Here you can add data from your computer, an ArcGIS Online or Enterprise organization, or the Living Atlas.
- In the Add Data window, under Portal, click Living Atlas.
- In the search bar, type World Countries owner: esri.
- Select the World Countries feature layer and click OK to add it to the map.
The World Countries layer is added to the map.
- In the Add Data window search for World Administrative Divisions owner:esri_dm and add the World Administrative Divisions layer.
The World Administrative Boundary layer's visibility is restricted to specific scales. You may need to zoom in to see the layer. The layer refers to administrative level 1 boundaries for countries, which may be analogous to regional or state boundaries.
Next, you'll select and extract the country and administrative boundaries for the Democratic Republic of the Congo into two new feature layers.
- On the ribbon, click the Analysis tab. In the Geoprocessing group, click Tools.
- In the Geoprocessing pane, search for and choose the Feature Class to Feature Class tool.
- In the Feature Class to Feature Class tool, for Input Features, choose World_Countries.
- For Output Location, ensure you are using the default project geodatabase named MalariaEpidemics.gdb.
- For Output Feature Class, name the new feature class DRC_Country.
- Click Add Clause to construct a new query.
You'll construct an SQL query to select and export the Democratic Republic of the Congo features from the World Countries layer.
- In the expression builder, use the drop-down menus to build the following statement: COUNTRY is Equal to Congo DRC. Press Enter to input the clause.
The Democratic Republic of the Congo and The Congo are two different countries. For this lesson, you are focusing on the Democratic Republic of the Congo, referred to here as Congo DRC.
- Click Update to complete the statement.
- Above the expression, click the green check mark to verify that the expression is valid.
The Field Map controls which attributes from the original feature layer, World Countries, will carry over to the new feature layer, DRC_Country. Unnecessary attributes increase file size, so you'll remove all unneeded attributes.
- For Field Map, for Output Fields, remove the following by selecting and pressing the red X: ISO CC, Continent, LAND_TYPE, LAND_RANK, and COUNTRYAFF.
- Click Run.
After the tool runs, the DRC_Country layer is added to the Contents pane. You no longer need the World Countries layer, so you'll remove it.
- In the Contents pane, right-click the World Countries layer and choose Remove.
Now you'll follow the same workflow to extract administrative boundaries for the Democratic Republic of the Congo from the World Administrative Divisions layer into a new feature class.
- Open the Feature Class to Feature Class tool.
- Set the tool parameters to the following:
- For Input, choose World Administrative Divisions.
- Ensure Output Location is set to MalariaEpidemics.gdb.
- For Output Feature Class, type DRC_Admin.
- For SQL Expression, build the following statement: Country is Equal to Congo DRC.
- For Output Fields remove all fields except NAME.
- Click Run.
In the Contents pane, you'll now see a DRC_Admin layer.
- Remove the World Administrative Divisions layer.
You now have two layers: the country boundary for the Democratic Republic of the Congo and the administrative level 1 boundary for the country.
- Close the Geoprocessing pane.
- Press Ctrl+S to save your project.
Merge multiple features
Some boundary layers may have multiple features that are considered part of the same area. For example, the DRC_Country feature class contains three, instead of one, country border features all considered part of the Democratic Republic of the Congo. The DRC_Admin feature class has a similar problem of three Bas-Congo features. These three features correspond to the same area in both files and, in both files, they need to be merged into a single feature before proceeding.
- In the Contents pane, right-click the DRC_Country layer and choose Zoom To Layer.
The Democratic Republic of the Congo should now be fully visible in the center of your screen. You'll merge the three separate country features into one feature.
- Right-click the DRC_Country layer and choose Attribute Table.
Notice that there are three polygons designated as the country border. The feature with the largest area can be assumed to be the main country border, but you should always check the other features.
- In the attribute table, click the second row to select it.
The selected row should be highlighted in light blue.
- At the top of the attribute table, click Zoom To.
The map zooms to show the features you selected. You can see that these features are mostly small islands within the Congo river that form part of the country border.
- In the attribute table, click the third row to select it.
In the map pane, larger islands along the river border are now highlighted. You have confirmed that the other two feature classes are indeed part of the country's border. You'll merge the three features into one using the Merge tool.
- On the ribbon, click the Edit tab. In the Tools group, choose Merge to open the Modify Features pane.
The tools on the Edit tab are separate from the tools you would find in the Geoprocessing toolbox. They are exclusively accessed and used on the Edit tab for common editing workflows and when editing is performed, you have the option to save or discard the changes.
- In the DRC_Country attribute table, press Ctrl+A to select all features. Ensure all features are highlighted.
- In the Modify features pane, click Merge.
The attribute table now contains only a multi-part feature that consists of several geometries, but has only one attribute record. To make these changes permanent, you need to save your edits.
- On the Edit tab, in the Manage Edits group, click Save. Click Yes to confirm.
- On the Edit tab, in the Selection group, click Clear to deselect all features.
Now you'll merge multiple features in the DRC_Admin feature class. The DRC_Admin layer contains three features with the name of Bas-Congo that need to be merged into a single feature.
- Open the DRC_Admin attribute table.
- On the Edit tab, in the Tools group, click Merge to open the Modify Features pane.
- In the DRC_Admin attribute table, select the three Bas-Congo features.
You can select multiple features by pressing Ctrl while clicking more rows.
- Click Merge.
- Close the attribute tables and Modify Features pane.
- Save your edits.
- Press Ctrl+S to save your project.
In this lesson, you added global boundary data from the Living Atlas, extracted specific country features, and merged multiple features into a single feature. In the next lesson, you'll add population estimate data from the Living Atlas and calculate the estimates within your boundaries.