Vector Symbolization

In map production, symbolization is the core process of converting abstract geographic data into visual information. A symbol is the visual unit used to represent geographic features, while a style defines the specific visual properties of a symbol, such as color, size, and fill. Symbolized rendering of vector layers helps show category differences, class distributions, and quantitative characteristics of geographic features clearly.

Layer Symbolized Rendering

Layer symbolization means applying rendering rules to display features on a map based on their attributes. iXGIS supports multiple rendering methods, including single symbols, unique values, and graduated symbols.

Single Symbol

Single symbol rendering is the most basic rendering method. All geographic features in a layer are displayed with the same symbol, style, color, and size.

• Use cases: Use this method when you do not need to distinguish features by attribute and only need to show their spatial distribution, such as administrative boundaries, monitoring camera locations, or building footprints in a basemap.
• How to configure: In the layer style panel, select Single symbol, then choose a symbol from the symbol library or customize one.

Unique Values

Unique values rendering assigns different symbols to each feature category based on the values of a qualitative field in the attribute table, such as type, level, or name.

• Use cases: Use this method to classify geographic features. For example, classify polygon features by a land use type field into farmland, woodland, and grassland, or distinguish expressways, national roads, and provincial roads by a road class field.
• Configuration options:
  • Category field: Select the attribute field used for classification.
  • Color scheme: Select a preset color scheme or manually assign a symbol to each category.
  • Default symbol: Display features whose field value is empty or not included in the category list.

Graduated Symbols

Graduated symbols, including graduated colors and graduated sizes, divide the values of a quantitative field in the attribute table into several classes and assign different colors or symbol sizes to each class.

• Graduated rendering types:
  • Graduated colors: Use changes in color shade or hue to represent value magnitude. This is often used in thematic maps, such as population density or rainfall classification maps.
  • Graduated sizes: Use changes in point symbol diameter or line width to represent value magnitude. This is often used to show intensity or totals, such as city GDP totals or earthquake magnitude distribution.
• Classification methods: iXGIS supports several statistical classification methods:
  • Natural breaks: Classifies data based on natural groupings, minimizing variation within classes and maximizing variation between classes.
  • Quantile: Places the same number of features in each class. This is suitable for evenly distributed data.
  • Equal interval: Divides the range of attribute values into subranges of equal width.
  • Standard deviation: Shows how far feature attribute values deviate from the mean. This is useful for identifying outliers.
• Configuration options:
  • Graduation field: Select a numeric field.
  • Number of classes: Set the number of classes to create.
  • Color scheme/size range: Set the color ramp or the minimum and maximum symbol sizes.

Symbol Manager

Overview

The Symbol Manager is a centralized graphic style resource management module for creating, editing, storing, and applying symbol styles for vector data. It supports unified management of point, line, and polygon feature symbolization, making it easier to standardize symbols, reuse styles, and maintain consistency in map production.

Use Cases

Scenario	Description
Map production standardization	Manage layer style specifications consistently in large map production projects to ensure symbol consistency and readability.
Thematic map design	Quickly switch to the appropriate style library for different themes, such as land use, pipeline distribution, or risk assessment.
Multi-user collaborative mapping	Share unified style resources when multiple users edit a map project, avoiding inconsistent styles.
Rapid emergency mapping response	Apply emergency symbol schemes quickly through style templates for events such as floods or earthquakes.
Style template development and customization	Customize dedicated symbol style libraries for governments and enterprises, such as public security, environmental protection, or transportation departments.

Symbol Categories

• Point symbol library: Point symbols represent geographic features that have a spatial location but no direction or extent, such as trees, wells, monitoring stations, buildings, and landmarks.

  Style properties:

  Property	Description
  Symbol shape	Circle, square, triangle, star, cross, icon (SVG/PNG), or custom shape.
  Fill color	Single color.
  Stroke style	Color, width, and line type, such as solid, dashed, or dash-dot.
  Size	Fixed size or controlled by an attribute field as proportional symbols.
  Rotation angle	Supports manual settings or rotation by direction from an attribute field.

  Use cases: Urban facility point maps, such as fire hydrants and utility poles; environmental monitoring station distribution maps; and pipe network manhole marker maps.

• Line symbol library: Line symbols represent features with direction and extent, such as roads, rivers, pipelines, and boundaries.

  Style properties:

  Property	Description
  Line type	Solid line, dashed line, dotted line, arrow line, and others.
  Line width	Fixed value.
  Color	Single-color symbol.
  Pattern line	Supports vector pattern lines or repeated custom graphic symbols.
  Endpoint style	Square, butt, round, and others.

  Use cases: Road network mapping, flow direction maps such as water or electric current, administrative boundaries, and pipe network representation.

• Polygon symbol library: Polygon symbols fill area features with closed boundaries, such as lakes, land use areas, building footprints, and administrative zones.

  Style properties:

  Property	Description
  Fill type	Solid fill, pattern fill such as dot or line patterns, gradient fill, or image fill.
  Opacity	Supports adjustment from 0% to 100%.
  Stroke style	Color, width, line type, dashed line, and others.
  Multilayer fill	Supports mixing a base fill with an overlay pattern.

  Use cases: Land use/land cover classification maps, building zoning diagrams, and risk distribution maps such as flood inundation areas or high-temperature zones.

Modify and Save Symbols

• In the content list, click the symbol you want to modify.
• In the symbol editor dialog, select the symbol to change. Double-click the symbol to display features with the new symbol settings.
• For advanced symbol settings, add or modify symbol components in the symbol list.
• Click Save. In the dialog that appears, enter a name for the new symbol and click Confirm.

My Symbols

After a symbol is saved, you can view it in private styles.

Create Symbols

Based on their basic characteristics, symbols can be divided into point symbols, line symbols, and polygon symbols. New symbols are created in the symbol editor.

Create Point Symbols

Point symbols are used for geographic features distributed as points. Point symbols include simple symbols, SVG symbols, character symbols, and image symbols.

• Simple marker: A marker symbol composed of quickly drawn basic symbol patterns with optional outlines.
• SVG marker: A marker symbol based on scalable vector graphics.
• Character marker: A marker symbol created from glyphs in text or display fonts in the system font folder.
• Image marker: A marker symbol composed of a single PNG, JPEG, GIF, Windows bitmap, or Windows enhanced metafile graphic.

Simple Point Symbol

• Open the marker property editor to customize the appearance parameters of the point marker.
• In the Type drop-down list, select Simple marker to enable style configuration for basic shapes such as circles, squares, and stars.
• Under Fill, set the color, size, shape, and angle:
  • Color: Select the marker fill color.
  • Size: Set the graphic size of the marker.
  • Shape: Select the required shape from preset graphics, such as circle, square, or diamond.
  • Angle: Set the marker rotation angle in degrees to adjust the graphic direction.
• Under Offset, set the horizontal and vertical offsets:
  • Horizontal offset: Move the marker along the X-axis.
  • Vertical offset: Move the marker along the Y-axis.
• Under Anchor, select horizontal and vertical alignment, such as left, center, right, top, middle, or bottom, to determine the marker reference point.
• After enabling Stroke, set the stroke type, line width, and color:
  • Stroke type: Select the line style, such as solid or dashed.
  • Line width: Set the stroke thickness.
  • Color: Define the stroke color.

SVG Point Symbol

• Open the marker property editor to customize the appearance parameters of the point marker.
• In the Type drop-down list, select SVG marker to enable vector graphic-based symbol customization.
• Under Fill, set the color, height, width, and angle:
  • Color: Set the fill color of the SVG graphic.
  • Height: Define the display height of the SVG graphic to adjust its size on the map.
  • Width: Set the display width of the graphic to scale or stretch the symbol as needed.
  • Angle: Set the rotation angle of the graphic in degrees to control its orientation.
• Under Offset, set the horizontal and vertical offsets:
  • Horizontal offset: Fine-tune the marker position along the X-axis.
  • Vertical offset: Fine-tune the marker position along the Y-axis.
• Under Anchor, select horizontal and vertical alignment, such as left, center, right, top, middle, or bottom, to determine the marker reference point.
• In the SVG library section, browse and select a symbol category library, such as:
  • Transportation: Traffic signs, vehicles, and road-related icons, such as buses, subways, and parking lots.
  • Housing: Homes, buildings, and building structures.
  • Amenities: Restrooms, ATMs, vending machines, drinking water locations, and other daily service facilities.
  • Health: Hospitals, clinics, first-aid stations, pharmacies, and health service locations.
  • Global positioning system: Location icons, target points, signal signs, and navigation direction arrows.
  • Public services: Police stations, fire stations, municipal facilities, and government offices.
  • Crosses: Symbols used to indicate prohibited, closed, invalid, or error states, such as X or cross graphics.
  • Landmarks: Towers, monuments, statues, scenic spots, and other prominent geographic or cultural markers.
  • Entertainment: Cinemas, theaters, museums, karaoke venues, arcades, and other leisure places.
  • Religion: Churches, temples, mosques, religious symbols, and others.
  • Travel: Luggage, hotels, airports, passports, route maps, and other travel-related icons.

Character Point Symbol

• Open the marker property editor to set the visual style and positioning method of the point marker.
• In the Type drop-down list, select Character marker to enable font character-based symbol display. This is suitable for symbolizing letters, numbers, or special characters.
• Under Character, set the font, style, color, angle, and size:
  • Font: Select the font family.
  • Style: Set the font style, such as regular, bold, or italic.
  • Color: Set the character fill color.
  • Angle: Define the character rotation angle in degrees to adjust the symbol orientation.
  • Size: Set the character display size to control its visual scale on the map.
• Under Offset, set the horizontal and vertical offsets:
  • Horizontal offset: Move the marker along the X-axis.
  • Vertical offset: Move the marker along the Y-axis.
• Under Anchor, select horizontal and vertical alignment, such as left, center, right, top, middle, or bottom, to determine the marker reference point.
• Open the Character symbol library and select the required symbol characters, such as arrows, direction indicators, or graphic symbols, to represent specific meanings or categories.

Image Point Symbol

• Open the marker property editor to set the visual style and positioning method of the point marker.
• In the Type drop-down list, select Image marker to enable image file-based symbol display, such as PNG, JPG, or BMP.
• Select an image file from a local path or resource library and import it as the marker image.
• Under Fill, set the width, height, opacity, and angle:
  • Width: Set the display width of the image on the map, usually in points or pixels.
  • Height: Define the display height of the image.
  • Opacity: Adjust the image opacity from 0% to 100% to achieve different visual blending effects.
  • Angle: Set the marker rotation angle in degrees to adjust the graphic direction.
• Under Offset, set the horizontal and vertical offsets:
  • Horizontal offset: Move the marker along the X-axis.
  • Vertical offset: Move the marker along the Y-axis.
• Under Anchor, select horizontal and vertical alignment, such as left, center, right, top, middle, or bottom, to determine the marker reference point.

Create Line Symbols

Line symbols are used for geographic features distributed as lines, such as rivers and roads. Line symbols include simple line symbols, image line symbols, and marker line symbols.

• Simple line symbol: The most common line symbol type. It quickly represents geographic features through basic line types and color properties.
• Image line symbol: Builds a line style from repeated images. It is often used for linear features with specific patterns, such as railways or power transmission lines.
• Marker line symbol: Forms a line style by placing point markers, such as arrows or small dots, along a line. It is suitable for representing direction or segment information, such as flow arrows or measurement marks.

Simple Line Symbol

• Open the line property editor to customize the visual style of line features.
• In the Type drop-down list, select Simple line symbol to enable basic line symbol configuration.
• Line type: Select the line style, such as solid or dashed.
• Line width: Set the line thickness in points or pixels. Wider lines are suitable for emphasizing major features, such as main roads or rivers.
• Color: Specify the line color using a color palette, RGB value, or color code to improve layer distinction and visibility.
• Join: Set the join style at polyline corners, which affects corner appearance:
  • Miter: Creates sharp corners, suitable for straight-line joins.
  • Round: Makes corners rounded and softer.
  • Bevel: Uses beveled corners, suitable for a modern appearance.
• Endpoint: Set the style of both line ends, which affects how line start and end points are handled:
  • Butt: Ends the line at a right angle.
  • Round: Ends the line with a semicircle for a smoother appearance.
  • Square: Extends half a line width beyond the endpoint to form a square end.

Image Line Symbol

• Open the line property editor to customize the visual style of line features.
• In the Type drop-down list, select Image line symbol.
• Select an image file from a local path or resource library and import it as the marker image.
• Line width: Set the line thickness in points or pixels. Wider lines are suitable for emphasizing major features, such as main roads or rivers.
• Join: Set the join style at polyline corners, which affects corner appearance:
  • Miter: Creates sharp corners, suitable for straight-line joins.
  • Round: Makes corners rounded and softer.
  • Bevel: Uses beveled corners, suitable for a modern appearance.
• Endpoint: Set the style of both line ends, which affects how line start and end points are handled:
  • Butt: Ends the line at a right angle.
  • Round: Ends the line with a semicircle for a smoother appearance.
  • Square: Extends half a line width beyond the endpoint to form a square end.
• Opacity: Adjust the image opacity from 0% to 100% to achieve different visual blending effects.

Marker Line Symbol

• Open the line property editor to customize the visual representation of linear geographic features, such as flows, paths, and boundaries.
• In the Type drop-down list, select Marker line symbol to place point markers such as arrows, dots, or characters along the line.
• Line width: Set the base line thickness in points or pixels. This represents the main body width of the line feature.
• Color: Specify the line color. It can match the marker color for consistency or contrast with it for emphasis.
• Interval: Set the spacing between repeated markers along the line in points or pixels. Smaller values create denser markers, while larger values create wider spacing. Use this to control the distribution density of arrows or symbols along the line.
• Position: Distribute markers by percentage along the line segment length.

Create Polygon Symbols

Polygon symbols represent geographic features distributed as areas, such as lakes and administrative regions. Polygon symbols include simple fill, gradient fill, line pattern fill, and point pattern fill.

• Simple polygon symbol: A quickly drawn single-color fill with an optional stroke.
• Gradient polygon symbol: A continuous fill using linear, rectangular, circular, or buffer color ramps.
• Line pattern fill polygon symbol: A pattern of evenly spaced parallel hatch lines with configurable angle and spacing.
• Point pattern fill polygon symbol: A random or evenly spaced pattern of repeated marker symbols.

Simple Polygon Symbol

• Open the polygon property editor to customize the visual representation of area features, such as lakes, building land, and administrative boundaries.
• In the Type drop-down list, select Simple polygon symbol to enable basic fill style configuration. This symbol type is suitable for most common polygon features.
• Select a fill color using the color picker to specify the main color of the polygon feature.
• Enable Stroke, then set the type, line width, and color:
  • Type (line type): Select the stroke line type, such as solid, dashed, or dash-dot.
  • Line width: Set the stroke thickness in points or pixels.
  • Color: Specify the stroke color to strengthen boundary contrast or distinguish the feature from the background.

Gradient Polygon Symbol

• Open the polygon property editor to customize the visual representation of area features, such as lakes, building land, and administrative boundaries.
• In the Type drop-down list, select Gradient polygon symbol to configure a gradient fill style. Gradient fills can improve the visual hierarchy and appearance of polygon symbols and are suitable for emphasizing internal structure or intensity changes.
• Select either two-color or color series gradient fill:
  • Two-color: Uses two specified colors for a linear or radial gradient fill. This is suitable for simple visual transitions.
  • Color 1: Set the start color of the gradient.
  • Color 2: Set the end color of the gradient.
  • Angle: Specify the gradient direction in degrees. For example, 0 degrees means left to right, and 90 degrees means bottom to top.
  • Gradient type: Select the gradient style. Options include linear, where colors transition evenly from start to end, and circular, where colors radiate from the center outward. Preset color ramps are suitable for representing continuous changes in class, density, or intensity.
  • Color series: Select a suitable gradient color series from the color ramp library, such as green to red or blue to white.
  • Angle: Set the rendering direction of the color ramp inside the polygon.
  • Gradient type: Select the gradient style. Options include linear, where colors transition evenly from start to end, and circular, where colors radiate from the center outward.
• Enable Stroke, then set the type, line width, and color:
  • Type (line type): Select the stroke line type, such as solid, dashed, or dash-dot.
  • Line width: Set the stroke thickness in points or pixels.
  • Color: Specify the stroke color to strengthen boundary contrast or distinguish the feature from the background.

Line Pattern Fill Polygon Symbol

• Open the polygon property editor to customize the visual representation of area features, such as lakes, building land, and administrative boundaries.
• In the Type drop-down list, select Line pattern fill to fill polygon features with repeated line patterns. This type is often used for polygon features that require specific pattern representation, such as restricted areas, engineering zones, and functional zones.
• Under Line pattern, set the color, interval, and angle:
  • Color: Set the line color used for the pattern fill. Standard palettes and custom RGB colors are supported.
  • Interval: Specify the spacing between lines in points or pixels. Smaller values create denser patterns, while larger values create sparser patterns.
  • Angle: Set the line tilt angle in degrees to control the line direction.
• Enable Stroke, then set the type, line width, and color:
  • Type (line type): Select the stroke line type, such as solid, dashed, or dash-dot.
  • Line width: Set the stroke thickness in points or pixels.
  • Color: Specify the stroke color to strengthen boundary contrast or distinguish the feature from the background.

Point Pattern Fill Polygon Symbol

• Open the polygon property editor to customize the visual representation of area features, such as lakes, building land, and administrative boundaries.
• In the Type drop-down list, select Point pattern fill to fill areas with repeated point markers, such as dots, stars, or symbols. This type is suitable for areas that require patterned representation, such as park green space, restricted areas, and engineering areas.
• Under Marker pattern, set the color, horizontal spacing, and vertical spacing:
  • Color: Set the color of point symbols in the fill pattern. Choose a color with sufficient contrast against the basemap or fill background to improve readability.
  • Horizontal spacing: Specify the spacing of the point pattern in the horizontal direction along the X-axis, in points or pixels. This controls the horizontal density of points.
  • Vertical spacing: Set the spacing of the point pattern in the vertical direction along the Y-axis. This controls the vertical density of points.
• Enable Stroke, then set the type, line width, and color:
  • Type (line type): Select the stroke line type, such as solid, dashed, or dash-dot.
  • Line width: Set the stroke thickness in points or pixels.
  • Color: Specify the stroke color to strengthen boundary contrast or distinguish the feature from the background.

Relationship Between Symbols and Styles

In iXGIS, symbols and styles are closely related and form the core of map visual representation. Together, they determine how geographic features appear on the map and how efficiently information is communicated. They combine the content and form of cartographic representation.

Symbol

A symbol is the content carrier of map representation. It is the visual element used to represent spatial features and convert geographic information on a map into visual marks. Based on feature geometry type, symbols can be divided into the following categories:

• Point symbol: Represents objects that have a location but no area, such as wells, trees, and substations.
• Line symbol: Represents linear features, such as roads, rivers, and power transmission lines.
• Polygon symbol: Represents features with extent or area, such as buildings, green space, and water bodies.

Symbols distinguish categories, highlight feature characteristics, and guide map reading. They are the most basic information-carrying units in map visualization.

Style

A style is the visual form of a symbol. It defines the visual properties and appearance of a symbol and provides the visual modification and enhancement applied to the symbol. It includes, but is not limited to, the following properties:

• Color: Controls the main color and recognizability of the symbol.
• Size/line width: Determines the visual weight of point or line symbols.
• Shape: Affects graphic recognizability and symbolization logic.
• Fill method: Includes solid color, gradient, pattern, and others.
• Opacity: Controls symbol occlusion and overlay hierarchy.
• Stroke style: Strengthens boundary recognition and is suitable for polygon features.
• Angle/rotation: Controls the direction of directional symbols.

Adjusting a style does not change the nature of the object represented by the symbol, but it can significantly improve the symbol's expressiveness and information communication on the map.

Relationship Between Symbols and Styles

The relationship between symbols and styles can be understood as the relationship between content and presentation:

• A symbol determines what is represented, meaning which type of geographic object it stands for.
• A style determines how it is represented, meaning the way it is displayed.

Both are required:

• Without a symbol, a style cannot be applied.
• Without a style, a symbol cannot communicate clear and intuitive spatial information effectively.

For example, a road symbol can use different colors, line widths, or pattern styles to distinguish its class, such as primary or secondary road; status, such as planned or built; or attribute, such as one-way or two-way.

Style Manager

In iXGIS, you can use the Style Manager to centrally manage and apply style resources. Its functions include:

• Style library access: Provides built-in standard style libraries, such as transportation, water resources, and buildings.
• Style editing: Supports customization of colors, fills, patterns, and other properties of existing styles.
• Style saving and reuse: Supports saving custom styles as style items for repeated use.
• Batch style application: Quickly applies a unified style to multiple layers or feature types.
• Classified rendering support: Works with attribute fields to automatically assign different styles to different feature categories.