Blazor-ApexMaps 0.3.0

Blazor-ApexMaps

A Blazor wrapper for ApexMaps: interactive geographic data visualization, with the whole option surface typed in C#.

<ApexMaps Options="_options" Height="440" />

@code {
    private readonly MapsOptions _options = new()
    {
        Geo = new GeoOptions { Map = GeoMaps.WorldCountries110m },
        Series =
        [
            new ChoroplethSeries
            {
                Name = "Unemployment rate",
                JoinBy = JoinSpec.Between("iso_a3", "code"),
                Data = [new { code = "FRA", value = 7.3 }, new { code = "DEU", value = 5.7 }],
            },
        ],
    };
}

That is the whole example. No geometry to find, host or parse, no script tag, no CDN reference, no stylesheet link, and no projection, palette, classification, legend, label or tooltip configuration: the defaults are meant to be publishable.

Live demos - one page per feature.

Versioning. This package tracks the core's version, as react-apexmaps, vue-apexmaps and ngx-apexmaps do, so 0.3.0 here speaks for apexmaps@0.3.0. The core is phase 1: the engine, the five series, the registry and everything in the table below are working and tested, and the option surface may still move before 1.0.

What you get

† Licensed feature. It works without a key so you can evaluate it, with a watermark on the map. See Licensing.

Installation

dotnet add package Blazor-ApexMaps

// Program.cs
using Blazor_ApexMaps.Extensions;

builder.Services.AddApexMaps();

@* _Imports.razor *@
@using Blazor_ApexMaps.Components
@using Blazor_ApexMaps.Models

That is all the setup there is. The package carries the apexmaps core as an ES module and imports it itself, and the core injects its own stylesheet, so there is nothing to add to index.html or App.razor.

Geometry

Finding, converting and hosting boundaries is the tax on every map project, and it is paid before any chart is drawn, so the geometry is part of the product:

Geo = new GeoOptions { Map = GeoMaps.WorldCountries110m }  // canonical id
Geo = new GeoOptions { Map = GeoMaps.WorldCountries }      // detail-free: the lightest one
Geo = new GeoOptions { Map = GeoMaps.Us }                  // states, with albersUsa
Geo = new GeoOptions { Map = GeoMaps.JapanPrefectures }    // the country's own word for its tier
Geo = new GeoOptions { Map = GeoMaps.EuNuts2 }             // Eurostat regions
Geo = new GeoOptions { Map = "https://example.com/districts.json" }        // your own URL
Geo = new GeoOptions { Map = MapSource.FromGeometry(myGeoJsonObject) }     // geometry in hand

Nothing is fetched until a pack is named, and one pack is one request however many maps on the page ask for it. Each pack carries a recommended join key, a recommended projection where the generic default would be wrong, and its provenance.

Packs come from the apexmaps-geo package on jsDelivr by default, so nothing needs installing. For an offline or air-gapped app, publish that package's files under wwwroot and point the library at them:

builder.Services.AddApexMaps(options =>
{
    options.GeoSource = "/apexmaps-geo/";
});

ApexMapsRuntimeService reaches the rest of the registry at runtime: RegisterMapAsync (any geometry under an id of your own, including a floor plan drawn against the identity projection), RegisterPaletteAsync, ListMapsAsync, ListProjectionsAsync, ListPalettesAsync and MapMetaAsync for a pack's source, licence, attribution and vintage.

The component

<ApexMaps @ref="_map"
          Options="_options"
          Series="_series"
          Map="@GeoMaps.UsStates"
          Height="480"
          Width="@("100%")"
          Class="my-map"
          AutoUpdate="true"
          OnFeatureClick="OnFeatureClick"
          OnSelectionChange="OnSelectionChange" />

Options is the whole tree; Series, Map, Width and Height are shorthands for the parts of it that change most often. With AutoUpdate on (the default), a parameter change is compared against what was last sent to the browser and applied the cheap way where it can be: a change confined to the series tweens fills and radii rather than rebuilding the DOM, and a changed map or projection reprojects. A parent that rebuilds its options object on every render is not a redraw.

Methods

Take a @ref and drive the map directly:

await _map.UpdateSeriesAsync(nextSeries);                              // tweens
await _map.UpdateOptionsAsync(new MapsOptions { Geo = new GeoOptions { Projection = Projections.Mercator } });
await _map.FlyToAsync(new CameraTarget { Center = new LonLat(2.35, 48.85), Zoom = 8 });
await _map.FrameFeatureAsync("FRA", new FrameOptions { Padding = 40 });
await _map.ResetViewAsync();
await _map.ZoomInAsync(); await _map.ZoomOutAsync();
await _map.RotateToAsync(-25, -18);                                    // turns a globe
await _map.DrillToAsync("CA"); await _map.DrillUpAsync(int.MaxValue);
await _map.SetSelectionAsync("FRA", "DEU"); await _map.ClearSelectionAsync();
var diagnostics = await _map.DiagnoseJoinAsync();
var spec = await _map.GetSpecAsync();                                  // resolved options, as JSON
await _map.ExportPngAsync(new MapExportOptions { Scale = 2 });
var uri = await _map.GetDataUriAsync();

Events

All 17, as EventCallback parameters: OnRendered, OnUpdated, OnResized, OnFeatureClick, OnFeatureHover, OnFeatureFocus, OnMarkClick, OnMarkHover, OnClusterClick, OnDrilldown, OnDrillup, OnSelectionChange, OnLegendToggle, OnZoom, OnPanEnd, OnRotate, OnRotateEnd.

private void OnFeatureClick(FeatureEventArgs e)
{
    _selected = e.Key;                    // join key
    _label = e.Name;                      // display name
    _value = e.Value;                     // null where the feature had no data
    var row = e.Read<CountryRow>();       // the data row, as your own model
    var iso = e.Property("iso_a3");       // a geometry property
}

Formatters and accessors

The options that take a function in the core take one here too, as JavaScript source through JsFunction. They run per mark, per frame, or during projection, so a round trip to .NET for each of a few thousand features would be a stutter rather than a chart: the source travels as a string and is compiled once, in the browser.

Tooltip = new TooltipOptions
{
    Formatter = JsFunction.From("ctx => `<b>${ctx.name}</b>: ${ctx.value ?? 'no data'}`"),
},
Fill = new SeriesFillOptions
{
    Pattern = JsFunction.From("ctx => ctx.value > 55 ? ({ type: 'crosshatch' }) : null"),
},

A JsFunction is compiled with new Function, so it runs in the global scope: it can see window and anything your app put there, and it cannot see your C# variables. It is evaluated as code, so never build one from untrusted input.

Anything this wrapper does not model yet goes through AdditionalOptions, on MapsOptions and on every series, which is merged in with its keys written exactly as given.

Licensing

Dual licensed on the same terms as the rest of the family: a free Community License for individuals, non-profits, educators and organizations under $2M USD annual revenue, and a paid Commercial or OEM license above that. One key works across every Apex product, so an ApexCharts or ApexGrid customer does not buy a second one for maps. See LICENSE.

The line is that a map that answers a question is free, and a map that becomes an application is licensed.

Without a valid key the licensed features still work, in full, with a watermark on the map, so you can evaluate them in your own app with your own data. A valid key removes the watermark, without a reload. A map that uses none of them renders clean, with or without a key.

builder.Services.AddApexMaps(options =>
{
    options.LicenseKey = "APEX-xxxxxxxx";
});

Keys are per product, not per page: AddApexMaps and AddApexCharts set different copies of the licence manager, because each library bundles its own. An app with a chart and a map configures both, with the same key. Get a key at apexcharts.com/pricing.

The software licence does not cover the geographic data, which is published by third parties under its own terms: Natural Earth and US Census TIGER/Line are public domain, Eurostat GISCO NUTS is CC BY 4.0 and is credited on screen automatically. MapMetaAsync(id) says which is which.

Requirements

• .NET 9.0 or later
• Blazor WebAssembly or Blazor Server
• A browser with ES module support (every current one)

The demo app

git clone https://github.com/apexcharts/Blazor-ApexMaps.git
cd Blazor-ApexMaps
dotnet run --project src/Blazor-ApexMaps.Sample

One page per feature, so each loads on its own and cannot be broken by an unrelated one: choropleth, scales and palettes, projections and the globe, bubbles and markers, arcs and routes, drilldown, selection and linking, camera and export, theming and annotations, join diagnostics, and every event as it happens.

Development

dotnet build Blazor-ApexMaps.sln
dotnet pack src/Blazor-ApexMaps/Blazor-ApexMaps.csproj -c Release

# End-to-end: drive the sample in a real browser and fail on a page that draws nothing
dotnet run --project src/Blazor-ApexMaps.Sample --urls http://localhost:5186 &
cd tests/e2e && npm install && npx playwright install --with-deps chromium && npm test

The e2e smoke test is the one that matters for a wrapper: the whole contract lives in the interop layer and the core, so a mis-serialized option, a broken import path, an uncompilable formatter or a moved pack id would only surface at runtime. It loads every demo page in headless Chromium and fails on a console error, a visible Blazor error UI, a map that drew zero marks, an event that never reached .NET, or an export that produced nothing.

Project structure

src/Blazor-ApexMaps/
  Components/ApexMaps.razor        the component: parameters, methods, event bridge
  Models/                          the option tree, series, data rows, events, enums
  Interop/ApexMapsInterop.cs       the .NET side of the bridge
  Serialization/                   camelCase JSON, and JsFunction
  Services/ApexMapsRuntimeService  licence, geometry source, the registry
  wwwroot/js/blazor-apexmaps.js    the JS side of the bridge
  wwwroot/js/apexmaps.esm.js       the vendored apexmaps core
src/Blazor-ApexMaps.Sample/        the demo app, one page per feature
tests/e2e/                         headless browser smoke and interaction test

Related

• ApexMaps - the core library, with react-apexmaps, vue-apexmaps and ngx-apexmaps alongside it
• Blazor-ApexTree, Blazor-ApexSankey, Blazor-ApexGantt - the rest of the family
• ApexCharts

Support

• Issues: github.com/apexcharts/Blazor-ApexMaps/issues
• Licensing: apexcharts.com/pricing