exploring data

3.1: Identifying

4.1.1   Identifying features by pointing at them

Exercise using identify button find towns found at 4 corners of Ethiopia ·         East   __________________________________ ·         West  __________________________________ ·         North  __________________________________ ·         South __________________________________

1. Click the Identify button on the Tools toolbar. The Identify Results dialog box opens.

2. Click the mouse pointer over the map feature you want to identify. The features in the topmost layer under the pointer will be identified.

3.1.2 Displaying Map Tips

1. In the table of contents, right click the layer for which you want to display MapTips and click Properties.

2. Click the Display tab and check Show MapTips.

3. Click the Fields tab.

4. Click the Primary Display Field dropdown arrow and click the attribute field you want to display as the MapTip.

5. Click OK.

6. Move the mouse pointer over a feature to see the MapTip.

3.3 Selection

3.3.1 Selecting a feature by clicking it in the map

1. Click the Selection tab in the table of contents.

2. Click the layers you want to select from.

3. Click Selection, point to Interactive Selection Method, then click Create New Selection.

4. Click the Select Features tool.

5. Click the feature you want to select.

6. To select additional features, hold down the Shift key while clicking the features. To remove a feature from the selected set, click the Selection menu, point to Interactive Selection Method, and click Remove From Current Selection. Click a selected feature and it is deselected.

3.3.2 Selecting a feature by clicking it in the table

1.      Right-click a layer in the table of contents and click Open Attribute Table.

2. Select a feature in the table by clicking to the left of a record.

3. To select additional features, hold down the Ctrl key and click the features. To deselect a feature, hold down the Ctrl key and click the feature.

3.3.3 Select features by drawing

1. Click the Selection tab in the table of contents.

2. Click the layers you want to select from.

3. Click Selection in the Main Menu, point to Interactive Selection Method, then click Create New Selection.

4. Click Selection in the Main Menu and click Options.

5. Specify how you’d like to select features with the box and click OK.

6. Click the Select Features button.

7. Click and drag a box around the features you want to select.

8. To select additional features, hold down the Shift key as you drag the box. To remove a feature from the selected set, click the Selection menu, point to Interactive Selection Method, and click Remove From Current Selection. Drag a box around the features you want to deselect.

3.3.4  selection by  “Select by Attribute”

Select by attribute

1. Click Selection and click Select By Attributes.

2. Click the Layer dropdown arrow and click the layer containing the features you want to select.

3. Click the Method dropdown arrow and click a selection method.

4. Double-click a field to add the field name to the expression box.

5. Click an operator to add it to the expression.

6. Click Get Unique Values to see the values for the selected field. Double-click a value to add it to the expression.

7. To see if you’re using proper syntax or if the criteria you’ve entered will select any features, click the Verify button.

8. Click Apply. The status bar at the bottom of the ArcMap window tells you how many features are selected.

9. If you’re finished selecting s, click Close.

Making the Selection tab visible

1. Click Tools on the Main Menu and click Options.

2. Click the Table Of Contents tab.

3. In the Table Of Contents tab options, check the Selection box.

4. Click OK.

Zooming to selected features

1. Right-click the layer in the table of contents that contains selected features.

2. Click Selection and click Zoom To Selected Features. ArcMap zooms to the selected features.

Displaying the attributes of selected features

1. In the table of contents, right click the layer containing selected features and click Open Attribute Table.

2. Click Show Selected records. Records of the selected features display.

Exercise  ( add Watersheds_1999, wereda,   i.            Load the “basin” shapefile. Select the Tana basin using the SQL query builder (___________Selected) ii.            Select  “Hulet Ej Enese” woreda (___________Selected) iii.            Select  the following woredas  “Akobo”, “Limu Kosa”, “Dugda Bora”  and “Babile”  what pattern they have ________________________ iv.            Select woredas of Ethiopia whose total population is greater than 200000  v.            Select all woredas  of Ahmara region which have a population greater than 150,000 vi.            Select woredas whose15% total population is greater than 80000 vii.            From ethio woreda select woreda whose urban population is less than 30,000 and its rural population greater than 200000 viii.            Select wereda either its urban population is greater than 10000 or total population greater than 250000

3.3.5 Selecting features geographical location

To find out how much of each land use is within the noise contour, select only those parcels within the contour.

1. Click Selection and click Select By Location. The Select By Location dialog box guides you through creating a geographic query.

2. In the first box, click the dropdown arrow and click select features from.

3. In the second box, check parcels as the layer to select features from.

4. Click the dropdown arrow for the third box and click intersect. This will select those features in parcels that intersect the features of cnel65.

5. In the last box, click the dropdown arrow and click cnel65 as the layer to select by.

6. Click Apply. The selected parcels are outlined in a thick line.

7. Close the Select By Location dialog box. Notice that any parcel even partially inside the contour is included.

Select by location

1. Click Selection and click Select By Location.

2. Click the dropdown arrow and click a selection method.

3. Check the layers whose features you would like to select.

4. Click the dropdown arrow and click a selection method.

5. Click the dropdown arrow and click the layer you want to use to search for the features.

6. Check to use only the selected features.

7. Check Apply a buffer to the features in <layer> and set the distance within which to search for features.

8. Click Apply. ArcMap selects the features.

9. If you’re finished selecting features click Close.

Specifying how all layers highlight

1. Click the Selection menu and click Options.

2. Click the color box and click the color you want to use. For polygons, this is the color the edges highlight in. For points and lines, this is the color the entire feature highlights in.

3. Click OK.

Specifying how a specific layer highlights

1. In the table of contents, rightclick a layer and click Properties.

2. Click the Selection tab.

3. Click the third option and click the color you want.

4. Click OK. This setting overrides any setting you make with the Selection Options dialog box.

3. The third option is to use the “Selection” tool in the toolbox (this option directly exports the

selected features to a new layer) Make sure that you have the toolbox in your window   Go to “Analysis Tools” and select “select”

Identify the input feature i.e. the layer you want to select from

§ Identify the output feature i.e. the location where you want the new map with the selected features to be saved

§ Choose the expression: click on SQL and the SQL query window will open. Define your query following the method described in the previous section.