8.1 Page Layout Composition and Design Elements (Scale Bars, Legends, North Arrows)
Key Takeaways
- A Map Frame must be selected to link dependent layout elements like scale bars, north arrows, and legends to the appropriate map.
- Dynamic text automatically updates based on map properties (e.g., scale, coordinate system) or system properties (e.g., current date).
- Legends offer multiple fitting strategies, including dynamic filtering to only show features currently visible in the map frame's extent.
- North arrows can be configured to point to True North, Magnetic North, or Grid North, which is essential for accurate navigation and surveying maps.
- Grids and graticules are essential for coordinate reference, with measured grids providing a projected network and graticules showing geographic coordinates.
Page Layout Composition and Design Elements
Creating professional-quality map layouts is a core capability of ArcGIS Pro. A layout is a page composition containing one or more map frames, along with supporting marginalia such as legends, scale bars, north arrows, and dynamic text. For the Esri ArcGIS Pro Associate exam, you must deeply understand how these elements interact, how they are linked to map frames, and the detailed properties of each. A single ArcGIS Pro project can contain multiple layouts, each with a different page size, orientation, and purpose.
Map Frames and Layout Properties
The fundamental building block of a layout is the Map Frame. A layout can contain multiple map frames, which may reference the same map or different maps entirely. For instance, a main map frame might show a detailed view of a study area, while an inset map frame shows the broader regional context, often highlighting the extent of the main map using an extent indicator.
Activating a Map Frame
To navigate within a map frame on a layout (e.g., panning or zooming the map content without changing the layout page zoom), you must Activate the map frame. Once activated, the layout view temporarily acts like a map view, allowing you to manipulate the geographic data directly. You can deactivate it to return to layout page navigation. This is a crucial workflow concept frequently tested on the exam.
Map Frame Constraints
Map frames can be constrained to prevent accidental changes to their geographic extent or scale:
- None: The user can pan and zoom freely when the map frame is activated.
- Fixed Center and Scale: The map is locked at a specific location and scale. Panning and zooming are disabled.
- Fixed Scale: The user can pan the map, but the scale remains locked.
- Fixed Extent: The exact geographic bounding box is locked. Resizing the map frame on the page will alter the scale to maintain the geographic extent.
- Linked Map Frame: The extent is tied to another map frame (e.g., an inset map that always centers on the main map's extent).
Linking Elements to Map Frames
Most layout elements—such as scale bars, north arrows, legends, and grids—are dynamically linked to a specific map frame.
[!IMPORTANT] If a layout contains multiple map frames, you must ensure that each layout element is explicitly associated with the correct map frame in its element properties. For example, if you change the scale of the inset map, its associated scale bar must update, but the main map's scale bar should remain unchanged.
Dynamic Text
Dynamic text is layout text that automatically updates when its associated properties change. It is heavily utilized to ensure map metadata remains accurate without manual edits. Dynamic text tags in ArcGIS Pro use XML-like syntax, though they are usually inserted via the UI ribbon.
Categories of Dynamic Text
- System Tags: Display system-level information, such as the current date (
<dyn type="system" property="date"/>), time, or user name. - Project Tags: Display project metadata, such as the project name, project path, or the date it was last saved.
- Map Frame Tags: Display properties of a specific map frame, such as its scale, spatial reference (coordinate system), center coordinates, or rotation angle. If you change the map frame's coordinate system, the dynamic text updates instantly.
- Map Series Tags: Used extensively in Map Series to display page names, page numbers, or attribute values from the index layer.
Legends and Fitting Strategies
A Legend explains the symbology used in the map frame. ArcGIS Pro provides advanced controls for how legends handle changes in layer visibility, map extent, or symbol classifications.
Dynamic Legend Filtering
One of the most critical legend properties for cartography is the ability to "Only show features visible in the map extent." When this property is enabled on a legend item, the legend will dynamically add or remove classes based on whether those features are currently within the map frame's spatial extent. If you pan the map away from a specific geological unit, that unit automatically drops from the legend, keeping the marginalia clean and relevant.
Legend Fitting Strategies
When new layers are added or symbol classes expand, legends must adapt to fit within their designated space on the layout. ArcGIS Pro offers several fitting strategies in the legend properties:
- Adjust Frame: The legend frame expands or contracts to accommodate all items. (This is the default setting).
- Adjust Columns & Font Size: The legend introduces new columns or reduces text size to fit the content within the fixed frame boundary. This is highly useful for rigid layout templates.
- Adjust Columns: Forces the legend to add new columns rather than expanding vertically, keeping the font size intact.
- Scale Items: Scales the entire legend up or down proportionately to fit the frame.
- Manual Columns: The user manually specifies the number of columns and explicitly defines which items belong in which column.
Furthermore, legends offer extensive formatting options, including word wrapping for long layer names, custom spacing between patches and text, and the ability to convert the legend to graphics for manual, ungrouped editing (though this severs the dynamic link to the map data).
Scale Bars
A Scale Bar provides a visual indication of distance on the map. It is tied to the map frame's scale and coordinate system, and automatically updates if the map is zoomed or projected differently.
Configuring Scale Bars
When designing a scale bar, you must configure its Units (e.g., Miles, Kilometers) and its Division Values.
| Property | Description |
|---|---|
| Divisions | The number of primary segments the scale bar is divided into. |
| Subdivisions | How the first division is further split (e.g., a 1-mile division split into 4 subdivisions of 0.25 miles each). |
| Fitting Strategy | How the scale bar reacts when the map scale changes (e.g., "Adjust division value", "Adjust number of divisions", or "Adjust width"). |
[!TIP] If you set a scale bar to "Adjust division value" and zoom the map frame in, the physical length of the scale bar remains constant on the page, but the values it represents (e.g., from 10 miles to 8.5 miles) will change. To keep clean, rounded numbers (e.g., always showing intervals of 10), use "Adjust width" so the bar grows or shrinks physically on the layout page.
North Arrows
North Arrows indicate the orientation of the map. By default, a north arrow points to the top of the map frame, which usually corresponds to geographic north, depending on the coordinate system.
Types of North Alignments
ArcGIS Pro allows north arrows to point to three different definitions of "North":
- True North: Points toward the geographic North Pole (the axis of Earth's rotation). This requires the map frame to have a coordinate system that accurately defines true north at the center of the frame.
- Grid North: Points straight up along the Y-axis of the projected coordinate system grid. In many projections (like State Plane or UTM), Grid North deviates slightly from True North depending on your location relative to the central meridian.
- Magnetic North: Points toward the Earth's magnetic North Pole, which slowly shifts over time due to core convection. This requires a magnetic declination calculation, often set in the north arrow properties with a specific date or modeled using World Magnetic Model data.
Understanding the difference between True North, Grid North, and Magnetic North is crucial for navigation, surveying, and passing the exam.
Grids and Graticules
Grids and graticules provide a network of lines or tick marks over the map frame to indicate coordinates, offering a geographic frame of reference.
- Graticules: Display lines of latitude and longitude (geographic coordinates in degrees, minutes, and seconds). They often appear curved depending on the map projection.
- Measured Grids: Display a network of perpendicular lines based on projected coordinates (e.g., UTM meters or State Plane feet). They form perfect squares on the map.
- Reference Grids: Divide the map into an alphanumeric grid (e.g., A1, B2) commonly used in street maps, index maps, or emergency response atlases.
You can customize the interval of the grid lines, sync the grid interval to change dynamically based on the map scale, configure the appearance of the labels, and choose whether to show full lines, tick marks, or just border annotations.
When configuring a scale bar in ArcGIS Pro, you want the physical width of the scale bar on the layout to remain exactly the same, even if the map frame's scale changes. Which scale bar fitting strategy should you choose?
Which North alignment option for a North Arrow points along the Y-axis of the map frame's projected coordinate system?
You have a legend showing geological units. You want the legend to automatically remove geological units that are not currently visible within the map frame's extent. Which property must you enable?