- Video length: 2:23
Symbology is the use of symbols to represent the features and attributes of a map layer. For example, in a layer of cities, black circles might symbolize the cities. The size of the circles might be varied to symbolize each city's population. Symbols are defined by visual properties like shape, size, color, spacing, and (in 3D) perspective height. The choice of symbols is a central part of map design.
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Data for all quick-start tutorials is included in one download. To download the data, follow these steps:
Open the project
In this project, you'll make a map of bus routes, bus stops, and population density in Christchurch, New Zealand.
- Start ArcGIS Pro and sign in if necessary.
- On the start page, under your recent projects, click Open another project.
- On the Open page, under Open, click Computer and click Browse .
- On the Open Project dialog box, browse to Symbolize_map_layers.aprx and click OK.
The file will be in a tutorial data folder with the same name, such as C:\ArcGISProQuickstartData\Symbolize_map_layers.
The project opens with a map view of New Zealand. You'll zoom in to the study area of Christchurch. With a population of 381,800, Christchurch is the third-largest city in New Zealand.
- On the ribbon, confirm that the Map tab is selected. In the Navigate group, click the Bookmarks drop-down arrow and choose Christchurch Urban Area.
The Urban Area layer has been symbolized by default with a light-green fill color and a black outline.
Symbolize the urban area
The purpose of the Urban Area layer is to define the study area boundary. The solid fill obscures the basemap. You'll change the symbol to make the interior area hollow.
- In the Contents pane, click the Urban Area layer to select it.
The layer is highlighted in the Contents pane. On the ribbon, the Feature Layer contextual tab appears.
- On the ribbon, under Feature Layer, click the Appearance tab. In the Drawing group, click Symbology . The button is a split button—click the top half, not the drop-down arrow.
The Symbology pane opens. The symbology method is Single Symbol, which means that all features in the layer are drawn with the same symbol. In this case, the layer only has one feature.
- In the Symbology pane, click the symbol.
The pane changes to Format Polygon Symbol. You can choose a different symbol from the gallery or change the properties of the current symbol. You'll change the symbol properties.
- Under Format Polygon Symbol, click Properties.
Under Properties, Symbol is selected. You can now change basic properties of the symbol.
- Click the Color drop-down arrow. On the color palette, choose No Color.
- Click the Outline color drop-down arrow. On the color palette, choose Gray 70%.
- In the Outline width box, change the width to 2 pt.
The symbol properties are previewed in the window at the bottom of the pane.
- Click Apply to update the map and the Contents pane. Close the Symbology pane.
On the map, the urban area boundary is sharply defined and the basemap is visible inside it. Now you'll display the bus stops and bus routes.
- In the Contents pane, select the check boxes next to the Bus Stops and Bus Routes layers to turn them on.
The default symbology for both layers needs work. Also, the topographic basemap competes with the feature layers for attention. You'll choose a more neutral basemap.
- On the ribbon, click the Map tab. In the Layer group, click the Basemap drop-down arrow and choose Light Gray Canvas.
Before continuing, you'll save your changes.
- On the Quick Access Toolbar, click Save .
Symbolize the bus stops
The current symbol for the Bus Stops layer is a small circle. You'll replace it with a symbol that represents bus stops more appropriately.
- In the Contents pane, click the Bus Stops layer to select it.
- On the ribbon, under Feature Layer, click the Appearance tab. In the Drawing group, click Symbology .
- In the Symbology pane, click the symbol.
- Under Format Point Symbol, click Gallery.
- In the search box, type bus and press Enter.
Symbols related to the search term are found. Your search results may be different from those in the image, but they should include bus station symbols. (The symbol is called Bus Station, but it is suitable for bus stops.)
- Click the smallest bus station symbol to select it.
The map and Contents pane update with the new symbol. After choosing a symbol from the gallery, you can further modify its properties.
- In the Symbology pane, under Format Point Symbol, click Properties.
- Click the Color drop-down arrow. On the color palette, choose Cabernet (last row, last column).
- Change the size to 8 pt and click Apply.
- At the bottom of the Symbology pane, under the preview window, change the magnification setting to 400%.
The preview window shows that the Cabernet color is applied to the bus icon but not to the gray symbol outline. This is because the symbol has more than one layer.
- At the top of the Symbology pane, under Properties, click Layers .
The Bus Station symbol has two symbol layers: the bus icon and a white circle with a gray outline.
- Click the white circle to select this symbol layer.
Underneath the selected symbol layer, there are options for changing the symbol layer's properties.
- Click the Outline color drop-down arrow and choose Cabernet.
In the preview window, the bus icon and the symbol outline are the same color.
- At the bottom of the Symbology pane, click Apply. Close the Symbology pane.
The bus stop symbols look good, but they clutter the map. You'll set a visibility range on the layer so the symbols appear only when the map is zoomed in to a specific scale.
- In the Contents pane, select the Bus Stops layer if necessary.
- On the ribbon, under Feature Layer, click the Appearance tab if necessary. In the Visibility Range group, click the Out Beyond drop-down menu and choose 1:24,000.
The symbols disappear from the map. In the Contents pane, the layer's check mark is gray. This means that the layer is turned on but not visible at the current map scale.
- In the lower left corner of the map view, click the map scale drop-down menu and choose 1:24,000.
The map zooms in and the bus stops display.
- On the ribbon, click the Map tab. In the Navigate group, click Previous Extent to return to the full urban area.
Symbolize the bus routes
The bus routes are currently drawn with a single symbol. You'll open the layer's attribute table to look for information that might differentiate the routes.
- In the Contents pane, click the Bus Routes layer to select it.
- On the ribbon, under Feature Layer, click the Data tab. In the Table group, click Attribute Table.
The attribute table opens. It has a few attributes that might be useful to symbolize, such as the route name, the route direction, or the route type. For this map, you'll use the Type attribute.
- Scroll down through the table and look at the values in the Type field.
There are four route types:
- City connectors connect suburbs to the city.
- Suburban links connect inner suburbs to each other.
- Metro lines follow major roads.
- Ferries connect the suburb of Lyttelton to Diamond Harbour.
You'll represent each route type with a different color.
- Close the Bus Routes attribute table.
- On the ribbon, under Feature Layer, click the Appearance tab. In the Drawing group, click the Symbology drop-down menu and choose Unique Values.
- In the Symbology pane, under Value field, click the Field 1 drop-down menu and choose Type.
Now that you have specified the attribute to symbolize, the bottom portion of the Symbology pane shows an entry for each of the four route types. It also shows a fifth entry for all other values.
- Click the Color scheme drop-down arrow. At the bottom of the list of color schemes, select the Show names check box.
- Choose the Dark 2 (5 classes) color scheme.
Because there are only four unique values for this attribute, the <all other values> symbol isn't needed.
- In the Symbology pane, under Color scheme, click the More drop-down menu and click to clear the Show all other values check box.
Each type of route is now identified by color. You are still free to modify the symbol properties. You'll change the Ferry symbol because ferry routes are conventionally symbolized with dashed lines.
- In the Symbology pane, click the line symbol for Ferry.
- Under Format Line Symbol, click Gallery. In the list of symbols, click Ferry.
The symbol updates in the Contents pane and on the map.
- Close the Symbology pane.
Now, you'll symbolize the population in the Christchurch urban area to visualize the relationship between bus routes and population.
- In the Contents pane, select the Population check box to turn on the layer.
A dense layer of points covers the urban area. Each point is the center of a meshblock. A meshblock, like a United States census block, is a small area for which census data is collected. In this layer, each point stores the population of its meshblock.
- On the map, click a population point.
A pop-up shows the 2013 population for the meshblock associated with the point. If you click a location where many points are close together, several pop-ups will open. You can scroll through them using the arrows at the bottom of the pop-up window.
The current layer symbology represents the meshblock locations, not the population values. By drawing the layer as a heat map, you'll be able to see where population is concentrated.
- Close the pop-up window.
- In the Contents pane, click the Population layer to select it.
- On the ribbon, under Feature Layer, click the Appearance tab if necessary. In the Drawing group, click the Symbology drop-down menu and choose Heat Map.
The heat map displays. At the moment, it represents the density of the point locations, not their population values.
- In the Symbology pane, click the Weight field drop-down menu and choose Pop 2013.
Now the heat map shows how population is distributed. The most sparsely populated areas are blue. The most densely populated areas are yellow.
- Close the Symbology pane.
The heat map covers the bus routes, so you'll change the order of layers in the Contents pane.
- In the Contents pane, drag the Population layer beneath the Urban Area layer. Confirm that the Population layer is still selected in the Contents pane.
- Under Feature Layer, on the Appearance tab, in the Effects group, change the layer transparency to 70%. Press Enter.
The bus routes correspond well to the densely populated parts of the urban area.
- On the Quick Access Toolbar, click the Save button .
In this tutorial, you used methods such as Single Symbol, Unique Values, and Heat Map to symbolize map layers. You changed a symbol property to make the Christchurch urban area transparent. You worked with symbol drawing layers to modify the bus stop symbol. You used attribute values to set symbology when you drew a heat map based on population. You made sure that symbols would display at appropriate scales by setting a layer visibility range. You also set layer transparency so that the heat map would not overwhelm the bus routes.
There are more symbology methods to explore and many ways to modify and design symbols for your maps—a few resources are listed in the Related topics below. To be inspired by examples of maps designed with ArcGIS Pro and other ArcGIS applications, visit the Maps We Love site.