Symbology is essential for defining the visual appearance of map elements, including symbols, colors, patterns, and text. It also determines whether and how information from the attribute table is displayed for each layer.
To customize the symbology of a layer, right-click on the layer (e.g., “buildings”) and select “Symbology” to open the corresponding panel. Within the “Primary Symbology” options, several representation methods are available:
- Single Symbol: Applies the same symbol to all features in the layer.
- Unique Values: Assigns different symbols to categories based on one or more attribute fields.
- Graduated Colors: Uses a color range to represent numeric values.
- Bivariate Colors: Displays the relationship between two numeric fields using two color scales.
- Unclassed Colors: Represents continuous numeric values with a gradient, without classification.
- Graduated Symbols: Varies symbol size based on a numeric value.
- Proportional Symbols: Symbol size is directly proportional to the data value.
- Dot Density: Represents quantities with dots, effective for showing density.
- Charts: Displays data in graphical formats, such as bar or pie charts.
- Dictionary: Uses predefined rules and attributes to apply complex symbology.
- Heat map: Indicates concentration of points with color intensity.
The “Unique Values” option is commonly used to display categories based on a field, such as the “Type” field in the “buildings” layer. Select the field under “Field 1” and click “Add all values” under “Classes” to include all categories. If a class labeled “<all other values>” appears, it can be removed by right-clicking and selecting “Remove”. This method can be applied to other layers, such as “road_network” and “plant_cover”, to display categories based on their attribute fields.
Setting unique values is utilized to display the categories of a specific layer.
Proper organization of the “Contents” panel improves map readability. Activate the “List By Drawing Order” button to rearrange layers by dragging them. It is best practice to place polygon layers at the bottom, followed by lines, and point layers at the top.
By default, newly added layers may have generic names and symbols. To improve clarity, use the “Unique Values” option and assign meaningful names to each category using information from the attribute table. Each layer or category name can be edited by double-clicking on it. Ensure correct spelling and grammar, especially for final publication or sharing.
The left section shows the layers in their unformatted and uncategorized state, the middle section displays the categorized layers, and the right section highlights the corrected spelling and grammar of the layer names as they will appear in the final publication.
ArcGIS Pro offers an extensive symbol library. When a layer is loaded, it is often represented by a default symbol that may not suit the map’s purpose. To customize a symbol, such as for a point feature like “School” in the “buildings” layer, follow these steps:
- Double-click the symbol next to the layer in the “Contents” panel.
- In the “Symbology” panel, under the “Gallery” tab, choose an appropriate symbol or search by category name, such as “School”.
- Select the desired symbol from a category like “Primitives”.
- Under the “Properties” tab, go to “Appearance” and use the “Color” dropdown to change the color. Custom colors can be created using RGB values in the “Color Editor”.
- For line features, adjust line width under “Line width”. For polygons, use “Outline Color” and “Outline width” to customize border appearance.
- To change symbol size for point features, use the “Size” setting under “Properties”.
- Once the symbol is customized, click “Apply” to save the changes.
This process illustrates the selection and customization of symbols in ArcGIS Pro.
This procedure can be repeated for all relevant layers to match the symbology and specifications described in the manual or as defined in the project requirements.
Definition of symbol properties.
