Working with line features

Line features can be some of the most difficult features to label. Linear features should always follow the line, and be labeled above the line, almost as if the feature were underlining the label, but with a tiny bit of space underneath, as seen in the Figure 4.11. Look for the smoothest stretch near where you want to place the label, and generally horizontal, if you can manage it. It is still not appropriate to put spaces between letters, but you can put spaces between words on long stretches. Be careful not to add so much space that the reader has already forgotten the first part by the time they reach the second:

A widely used cartographic convention is to label water features in italics. The slight sense of motion that italics implies corresponds well to the fluidity of water. This can sometimes create some interesting issues when splining text along a line. A quick workaround can be to insert a space between two problem letters or shift the whole label by adding space at the beginning or between words.

When line features are represented as a polygon, such as with wide rivers, text may be centered inside the feature (that is, in the river), but following the remaining placement guidelines for linear features. As with point features, labels should never appear upside down to the map reader. Let's work on some line features:

1. Right-click on MajorMNRivers in the Contents pane and select Label. Notice that some rivers are labeled in multiple places.
2. Right-click again and select Labeling Properties. In the Label Class pane, select Position, and then click the Conflict Resolution icon. 
3. Expand Remove duplicate labels and select Remove All. This will leave you with one label per river, which is plenty at this scale. For smaller scale maps, you can use Remove within fixed distance to set a preferred distance between labels.
4. Click the Position icon, expand Placement, and select River Placement. This will spline the text along the river.
5. If some of the labels appear upside down, expand Orientation and make sure Align label to direction of line is not checked. While this can be useful for some specific applications, it can result in some labels appearing upside down. Avoid using this setting unless your particular use case requires labeling along feature direction.
6. Lastly, we'll change the symbol to match our style sheet, Open Sans, Light Italic, 10 pt. Click Apply, and notice that some city labels may move to accommodate the river labels.
7. Save this to a style, as we'll use it again for our lakes.

An exception to the splining rule for linear features is when you are labeling them with icons, such as highway shields. The MajorMNRoads layer contains interstates and US highways, so we'll label them each with their respective shields:

1. Right-click on MajorMNRoads in the Contents pane and select Label. Notice that the labels say only I or U, and, like the rivers, are repeated.
2. Right-click again and select Labeling Properties. We want to label interstates and US highways separately, so let's create a label class for interstates. Start by renaming Class 1 to Interstates.
3. Set the SQL clause to HWY_TYPE is Equal to I, and click Apply.
4. We need to get rid of the I and label the roads with their number, so in the Feature Layer context ribbon, on the Labeling tab, set the Field to HWY_SYMBOL.
5. In the Text Symbol section, select Shield 1 as the symbol style. This will convert all the road numbers to road numbers on an interstate shield.
6. Highway shields should always be horizontal, so in the Label Placement section of the ribbon, select Shield.
7. Clear out duplicate labels like we did with the rivers. In the Label Class pane, select Position, and then click the Conflict Resolution icon.
8. Expand Remove duplicate labels and select Remove All. Again, if you need periodic labels along the length, you can use Remove within fixed distance to set a preferred distance between labels.

Since we're building this map in black and white, we'll need a grayscale version of the shield. This can be a little tricky to build in ArcGIS Pro, but you can work around this by using a point file. For this exercise, we'll make one by copying our St. Paul file:

1. Right-click on the St. Paul layer and click Copy.  
2. Right-click on the Map Frame in the Contents pane and click Paste. This will put a second St. Paul layer in your map.
3. Rename it to ShieldCustomization and set the Point Symbol to the Shield 1 symbol in the Gallery. A point will appear to the east of the Twin Cities.
4. Switch to the Properties tab, click the Layers icon, and notice that there are two components to this symbol—a red crest and a blue shield base.
5. Select the red crest and set the Color to Black.
6. Select the blue shield and set the Color to White.
7. Click Apply, then click the Menu button to save it to a style.
8. Turn the ShieldCustomization layer off. You may remove it from the map if you wish.
9. Return to the Labeling properties for MajorMNRoads and set the Point Symbol under Callout to your new symbol.
10. Repeat the process for the US highways, creating a label class, setting the SQL clause to HWY_TYPE is Equal to U, and using Shield 7.