PointStyle Guide¶

Namespace: ThinkGeo.Core
Applies to: All ThinkGeo products (WPF, WinForms, Blazor, MAUI, GIS Server, etc.)

Overview¶

PointStyle controls how point features — hotels, capitals, crime incidents, sensor readings, or any other single-coordinate geometry — are drawn on the map. It supports three distinct rendering modes that share the same class:

Symbol mode — a built-in geometric shape (PointSymbolType enum: circles, squares, diamonds, triangles, etc.) filled and outlined with GeoBrush/GeoPen values.
Image mode — an external raster image (GeoImage) displayed at the point location, scaled with ImageScale or SymbolSize.
Font/character mode — a single character rendered in a GeoFont, optionally masked with an AreaStyle background.

All three modes use the same property set (SymbolSize, RotationAngle, Mask, MaskType, IsActive) and are attached to a layer the same way.

Constructors¶

Symbol mode — `PointSymbolType` + size + fill + outline¶

The most common constructor. Takes a shape type, pixel size, fill brush, and optional outline pen.

// Fill + outline
var pointStyle = new PointStyle(PointSymbolType.Circle, 12, GeoBrushes.Blue, new GeoPen(GeoBrushes.White, 2));

// Fill only (no outline overload — omit the GeoPen argument)
var pointStyle = new PointStyle(PointSymbolType.Circle, 4, GeoBrushes.DarkRed, new GeoPen(GeoBrushes.White, 2));

Sources: wpfHowDoI:Samples/VectorDataStyling/RenderPoints.xaml.cs, winformHowDoI:Samples/VectorDataStyling/RenderBasedOnScales.cs, mauiHowDoI:Samples/VectorDataStyling/CreatePointStyle.xaml.cs.

Scale-dependent sizes — pass different sizes per zoom range:

// Small dot at zoom levels 12-13
hotelsLayer.ZoomLevelSet.ZoomLevel12.DefaultPointStyle =
    new PointStyle(PointSymbolType.Circle, 4, GeoBrushes.DarkRed, new GeoPen(GeoBrushes.White, 2));
hotelsLayer.ZoomLevelSet.ZoomLevel12.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level13;

// Medium dot at zoom levels 14-15
hotelsLayer.ZoomLevelSet.ZoomLevel14.DefaultPointStyle =
    new PointStyle(PointSymbolType.Circle, 8, GeoBrushes.DarkRed, new GeoPen(GeoBrushes.White, 2));
hotelsLayer.ZoomLevelSet.ZoomLevel14.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level15;

// Large dot at zoom levels 16-20
hotelsLayer.ZoomLevelSet.ZoomLevel16.DefaultPointStyle =
    new PointStyle(PointSymbolType.Circle, 12, GeoBrushes.DarkRed, new GeoPen(GeoBrushes.White, 2));
hotelsLayer.ZoomLevelSet.ZoomLevel16.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

Source: winformHowDoI:Samples/VectorDataStyling/RenderBasedOnScales.cs.

Symbol mode — `GeoSolidBrush` with `GeoColor.FromArgb` (semi-transparent or fully transparent sentinel)¶

// Transparent sentinel for ClassBreakStyle
new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColors.Transparent))

// Semi-transparent colored fill
new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColor.FromArgb(alpha, 255, 0, 0)))

Source: wpfHowDoI:Samples/MapOfflineData/Vector/GenerateESRIGridFile.xaml.cs.

Image mode — `GeoImage`¶

Pass a GeoImage wrapping a file path (WPF/WinForms) or an async stream (MAUI). Use ImageScale (relative multiplier) or SymbolSize (absolute pixel size) to control the rendered dimensions.

// WPF / WinForms — file path
var pointStyle = new PointStyle(new GeoImage(@"./Resources/hotel_icon.png"))
{
    ImageScale = .25
};

// WinForms — larger background circle + scaled image icon layered in a FilterStyle
new PointStyle(PointSymbolType.Circle, 28, GeoBrushes.White, GeoPens.Red),
new PointStyle(new GeoImage(@"../../../Resources/drugs_icon.png")) { ImageScale = .60 }

// MAUI — async package file stream
_imageStyle = new PointStyle(new GeoImage(await FileSystem.OpenAppPackageFileAsync("hotel_icon.png")))
{
    SymbolSize = 40,
    IsActive = false
};

Sources: wpfHowDoI:Samples/VectorDataStyling/RenderPoints.xaml.cs, winformHowDoI:Samples/VectorDataStyling/RenderBasedOnFilters.cs, mauiHowDoI:Samples/VectorDataStyling/CreatePointStyle.xaml.cs.

Font/character mode — `GeoFont` + character string + fill brush¶

Renders a single character from a font at each feature location. Typically combined with a Mask background to make the character legible.

var symbolPointStyle = new PointStyle(new GeoFont("Verdana", 16, DrawingFontStyles.Bold), "@", GeoBrushes.Black)
{
    Mask = new AreaStyle(GeoBrushes.White),
    MaskType = MaskType.Circle
};

Sources: wpfHowDoI:Samples/VectorDataStyling/RenderPoints.xaml.cs, winformHowDoI:Samples/VectorDataStyling/RenderPoints.cs, mauiHowDoI:Samples/VectorDataStyling/CreatePointStyle.xaml.cs.

Static Factory Method¶

`CreateSimpleCircleStyle`¶

Shorthand for a solid filled circle with an outline. Commonly used when constructing styles as property values inside other style wrappers.

PointStyle.CreateSimpleCircleStyle(GeoColors.Yellow, 12, GeoColors.Black)
PointStyle.CreateSimpleCircleStyle(GeoColors.Gray, 12, GeoColors.Black)

Sources: winformHowDoI:Samples/VectorDataStyling/CustomStyles.cs, wpfHowDoI:Samples/VectorDataStyling/CustomStyles.xaml.cs, mauiHowDoI:Samples/VectorDataStyling/ExtendingStyles.xaml.cs.

Properties¶

These properties apply across all three constructor modes and are read back the same way. Source: blazorHowDoI:Shared/LayerBuilder.cs.

Property	Type	Description
`SymbolType`	`PointSymbolType`	The geometric shape used in symbol mode (Circle, Square, Diamond, Triangle, etc.).
`SymbolSize`	`float`	Size in pixels. For image mode this sets the rendered width/height directly; for symbol mode it controls the radius/extent of the shape.
`RotationAngle`	`float`	Rotation in degrees, applied clockwise around the feature's point.
`FillBrush`	`GeoBrush`	The fill color for symbol mode. Cast to `GeoSolidBrush` to read back the `GeoColor`.
`OutlinePen`	`GeoPen`	The outline pen for symbol mode.
`ImageScale`	`float`	Multiplier applied to the source image's natural size in image mode. `.25` = quarter size.
`Mask`	`AreaStyle`	Background shape drawn behind the symbol/character.
`MaskType`	`MaskType`	Shape of the mask — `MaskType.Circle`, `MaskType.Rectangle`, etc.
`IsActive`	`bool`	When `false` the style is skipped during rendering without being removed. Useful for toggling between styles added to the same `CustomStyles` collection.

Reading properties back (Blazor inspector pattern):

PointStyle targetPointStyle = featureLayer.ZoomLevelSet.ZoomLevel01.DefaultPointStyle;

PointSymbolType type = targetPointStyle.SymbolType;
float size            = targetPointStyle.SymbolSize;
float angle           = targetPointStyle.RotationAngle;

GeoPen pen            = targetPointStyle.OutlinePen;
GeoColor penColor     = pen.Color;
float penWidth        = pen.Width;

GeoColor fillColor    = ((GeoSolidBrush)targetPointStyle.FillBrush).Color;

Source: blazorHowDoI:Shared/LayerBuilder.cs.

Attaching a Style to a Layer¶

`DefaultPointStyle` — single-style case¶

hotelsLayer.ZoomLevelSet.ZoomLevel01.DefaultPointStyle =
    new PointStyle(PointSymbolType.Circle, 12, GeoBrushes.Blue, new GeoPen(GeoBrushes.White, 2));
hotelsLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

`CustomStyles` — multiple styles or mixing with TextStyle¶

Use CustomStyles when you need more than one PointStyle stacked on the same zoom level (e.g., a background circle + an icon image), or when combining with a TextStyle.

// Stack a background circle + a scaled image icon
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Clear();
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(
    new PointStyle(PointSymbolType.Circle, 28, GeoBrushes.White, GeoPens.Red));
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(
    new PointStyle(new GeoImage(@"./Resources/hotel_icon.png")) { ImageScale = .60 });
hotelsLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

Source: winformHowDoI:Samples/VectorDataStyling/RenderBasedOnFilters.cs.

Combine with a TextStyle:

var pointStyle = new PointStyle(PointSymbolType.Circle, 4, GeoBrushes.Brown,
    new GeoPen(GeoBrushes.DarkRed, 2));
var textStyle = new TextStyle("NAME", new GeoFont("Segoe UI", 12, DrawingFontStyles.Bold), GeoBrushes.DarkRed)
{
    TextPlacement = TextPlacement.Center,
    HaloPen = new GeoPen(GeoBrushes.White, 2),
    DrawingLevel = DrawingLevel.LabelLevel,
    AllowLineCarriage = true,
    YOffsetInPixel = -10
};

hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(pointStyle);
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(textStyle);
hotelsLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

Source: mauiHowDoI:Samples/VectorDataStyling/CreateTextStyle.xaml.cs.

Toggling between styles with `IsActive`¶

Add all styles to CustomStyles at setup, then flip IsActive at runtime instead of clearing and re-adding:

// Setup — all three added, only predefined is active initially
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(_predefinedStyle);   // IsActive = true (default)
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(_imageStyle);        // IsActive = false
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(_fontStyle);         // IsActive = false
hotelsLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

// Switch to image style at runtime
_predefinedStyle.IsActive = false;
_imageStyle.IsActive = true;
_fontStyle.IsActive = false;
await _layerOverlay.RefreshAsync();

Source: mauiHowDoI:Samples/VectorDataStyling/CreatePointStyle.xaml.cs.

Using `PointStyle` inside `ClassBreakStyle`¶

ClassBreakStyle assigns a different PointStyle to features based on a numeric column value. The pattern is identical to AreaStyle in a ClassBreakStyle: use a transparent sentinel for the lowest break and colored fills for the remaining thresholds.

var classBreakStyle = new ClassBreakStyle("PH");
const byte alpha = 180;
const int symbolSize = 10;

classBreakStyle.ClassBreaks.Add(
    new ClassBreak(double.MinValue,
        new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColors.Transparent))));
classBreakStyle.ClassBreaks.Add(
    new ClassBreak(6.2,
        new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColor.FromArgb(alpha, 255, 0, 0)))));
classBreakStyle.ClassBreaks.Add(
    new ClassBreak(6.83,
        new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColor.FromArgb(alpha, 255, 128, 0)))));
classBreakStyle.ClassBreaks.Add(
    new ClassBreak(7.0,
        new PointStyle(PointSymbolType.Circle, symbolSize, new GeoSolidBrush(GeoColor.FromArgb(alpha, 245, 210, 10)))));
// ... additional breaks ...

samplesLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(classBreakStyle);
samplesLayer.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;

Source: wpfHowDoI:Samples/MapOfflineData/Vector/GenerateESRIGridFile.xaml.cs, winformHowDoI:Samples/MapOfflineData/Vector/GenerateESRIGridFile.cs.

Using `PointStyle` inside `FilterStyle`¶

FilterStyle applies a group of styles only to features that match a column-value condition. Stacking a symbol background with an image icon inside a FilterStyle is the standard pattern for category-icon maps.

var drugFilterStyle = new FilterStyle()
{
    Conditions = { new FilterCondition("OffenseGro", "Drugs") },
    Styles = {
        new PointStyle(PointSymbolType.Circle, 28, GeoBrushes.White, GeoPens.Red),
        new PointStyle(new GeoImage(@"./Resources/drugs_icon.png")) { ImageScale = .60 }
    }
};

var weaponFilterStyle = new FilterStyle()
{
    Conditions = { new FilterCondition("OffenseGro", "Weapons") },
    Styles = {
        new PointStyle(PointSymbolType.Circle, 28, GeoBrushes.White, GeoPens.Red),
        new PointStyle(new GeoImage(@"./Resources/weapon_icon.png")) { ImageScale = .25 }
    }
};

Source: wpfHowDoI:Samples/VectorDataStyling/RenderBasedOnFilters.xaml.cs, winformHowDoI:Samples/VectorDataStyling/RenderBasedOnFilters.cs, mauiHowDoI:Samples/VectorDataStyling/CreateFilterStyle.xaml.cs.

Using `PointStyle` as a property value¶

PointStyle instances can appear as property values on other objects, not just directly on zoom levels. The CreateSimpleCircleStyle factory method is particularly convenient in these contexts.

// As properties of a custom style wrapper
var timeBasedPointStyle = new TimeBasedPointStyle
{
    TimeZoneColumnName = "TimeZone",
    DaytimePointStyle  = PointStyle.CreateSimpleCircleStyle(GeoColors.Yellow, 12, GeoColors.Black),
    NighttimePointStyle = PointStyle.CreateSimpleCircleStyle(GeoColors.Gray, 12, GeoColors.Black)
};

// As the inner style of a SizedPointStyle (scales point size by a column value)
var sizedPointStyle = new SizedPointStyle(
    PointStyle.CreateSimpleCircleStyle(GeoColors.Blue, 1),
    "population",
    500000);

Sources: winformHowDoI:Samples/VectorDataStyling/CustomStyles.cs, wpfHowDoI:Samples/VectorDataStyling/CustomStyles.xaml.cs, mauiHowDoI:Samples/VectorDataStyling/ExtendingStyles.xaml.cs.

Common Patterns and Pitfalls¶

CustomStyles.Clear() before re-assigning. When switching the symbol type at runtime (e.g., from a circle to an icon in response to a UI event), always call CustomStyles.Clear() before adding the new style — otherwise the old style remains and both render on top of each other. The IsActive approach described above avoids this issue entirely.

hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Clear();
hotelsLayer.ZoomLevelSet.ZoomLevel01.CustomStyles.Add(newPointStyle);
await layerOverlay.RefreshAsync();

ImageScale vs SymbolSize for image mode. ImageScale is a multiplier against the image's natural pixel dimensions (.25 = 25% of original size). SymbolSize is an absolute pixel target. Use ImageScale when your icon has a predictable natural size and you want it to scale proportionally; use SymbolSize when you need a specific rendered size regardless of source dimensions.

GeoPens named constants. GeoPens.Red and GeoPens.DimGray are pre-built GeoPen instances (equivalent to new GeoPen(GeoBrushes.Red, 1)). They are valid anywhere a GeoPen is accepted and are interchangeable with new GeoPen(GeoColors.Red, 1).

Refreshing after style changes. Changing a style at runtime has no visible effect until the overlay is refreshed:

await layerOverlay.RefreshAsync();  // or MapView.RefreshAsync() if you need all overlays

Source References¶

Sample	Namespace	PointStyle usage
`VectorDataStyling/RenderPoints`	WPF, WinForms	All three modes — symbol, image, font/character
`VectorDataStyling/CreatePointStyle`	MAUI	All three modes + `IsActive` toggling
`VectorDataStyling/RenderBasedOnScales`	WPF, WinForms, MAUI	Symbol mode; scale-dependent sizes via `DefaultPointStyle`
`VectorDataStyling/CreateTextStyle`	MAUI	Symbol mode + `TextStyle` in `CustomStyles`
`VectorDataStyling/RenderBasedOnFilters`	WPF, WinForms	Image + symbol stacking inside `FilterStyle`
`VectorDataStyling/CreateFilterStyle`	MAUI	Image + symbol stacking inside `FilterStyle`
`VectorDataStyling/CustomStyles`	WPF, WinForms	`CreateSimpleCircleStyle` as a property value; `SizedPointStyle`
`VectorDataStyling/ExtendingStyles`	MAUI	`CreateSimpleCircleStyle` as a property value
`Shared/LayerBuilder.cs`	Blazor	Reading `SymbolType`, `SymbolSize`, `RotationAngle`, `OutlinePen`, `FillBrush`
`MapOfflineData/GenerateESRIGridFile`	WPF, WinForms	`ClassBreakStyle` + `PointStyle` color ramp with transparent sentinel

PointStyle Guide¶

Overview¶

Constructors¶

Symbol mode — PointSymbolType + size + fill + outline¶

Symbol mode — GeoSolidBrush with GeoColor.FromArgb (semi-transparent or fully transparent sentinel)¶

Image mode — GeoImage¶

Font/character mode — GeoFont + character string + fill brush¶

Static Factory Method¶

CreateSimpleCircleStyle¶