ProEssentials WinUI NEXRAD Radar Reflectivity — 2D Contour Chart

A ProEssentials v11 WinUI 3 .NET 10 demonstration of real NEXRAD WSR-88D Level II radar data displayed as a 2D contour chart using the official NWS standard reflectivity color table. Real weather radar data from KFWS (Dallas/Fort Worth), March 4, 2025.

➡️ gigasoft.com/examples/120

The chart-configuration code is identical to the WPF and WinForms versions of this example. The ProEssentials API does not change between interfaces; only the window plumbing differs.

The pre-generated .bin file is included. Clone, build, run:

1. Clone this repository
2. Open NexradRadarWinUI.sln in Visual Studio 2026
3. Build → Rebuild Solution
4. Press F5

No Python required to display the radar chart.

The .bin file was generated from real NOAA public radar data using a two-step pipeline. The raw V06 file and all pipeline tools are included so you can generate your own data from any NOAA radar station.

KFWS20250304_110319_V06          ← Raw NEXRAD L2 V06 (NOAA public data, 17MB)
        │
        ▼  (choose one)
┌─────────────────────┐    ┌──────────────────────────────────────┐
│  Python Pipeline    │    │  C# Converter (no Python needed)     │
│  step2_extract.py   │    │  NexradConverter/NexradConverter.cs  │
│  step3_cartesian_   │    │  Uses SharpCompress for BZ2          │
│    bin.py           │    │  dotnet run -- V06file output.bin    │
└──────────┬──────────┘    └──────────────────┬───────────────────┘
           │                                   │
           └──────────────┬────────────────────┘
                          ▼
              sweep_ref_800x450.bin
              800×450 float32 little-endian
              ~1 km/pixel, dBZ values
                          │
                          ▼
              NexradRadar WinUI Chart

Requires: numpy, scipy (standard scientific Python stack)

# Step 2: parse NEXRAD V06 → polar array
python step2_extract.py

# Step 3: polar → 800×450 Cartesian grid → .bin
python step3_cartesian_bin.py

step2_extract.py saves sweep_polar.npz (intermediate). step3_cartesian_bin.py reads sweep_polar.npz and writes sweep_ref_800x450.bin.

cd NexradConverter
dotnet run -- ../KFWS20250304_110319_V06 ../sweep_ref_800x450.bin

Uses SharpCompress NuGet for BZ2 decompression. Produces identical output to the Python pipeline.

NOAA provides free public access to all WSR-88D Level II archives:

AWS S3 (recommended — fastest):

s3://noaa-nexrad-level2/YYYY/MM/DD/KXXX/KXXXYYYYMMDDhhmmss_V06

NOAA NCEI:

https://www.ncei.noaa.gov/access/severe-weather/radar

Replace KFWS with any WSR-88D station ID (e.g. KORD Chicago, KLAX Los Angeles, KATL Atlanta). The V06 format is identical across all stations.

sweep_ref_800x450.bin
─────────────────────
Size    : 1,440,000 bytes (800 × 450 × 4 bytes)
Layout  : 800×450 IEEE 754 float32, little-endian, row-major
Row 0   : south edge,  Row 449 : north edge
Col 0   : west edge,   Col 799 : east edge
Values  : dBZ reflectivity, range approximately -10 to 76
NaN     : 0x7FC00000 — no radar data at this pixel (~1 km/pixel)

C# reading:

float[] data = new float[800 * 450];
using var br = new BinaryReader(File.OpenRead("sweep_ref_800x450.bin"));
for (int i = 0; i < data.Length; i++) data[i] = br.ReadSingle();
// data[row * 800 + col] = dBZ at pixel (col, row)

43 color bands from -10 to 76 dBZ — the classic TV weather radar look. Implemented via SubsetColors anchor interpolation (not a preset):

NullDataValueZ — pixels equal to the null sentinel render transparent, allowing the geographic map background to show through where there is no radar coverage.

SubsetColors anchor interpolation — custom color table defined by 18 anchor points linearly interpolated across 43 bands. More flexible than any built-in preset — use the same technique to implement any published color standard.

GraphBmpFilename + BitBltZooming — geographic map background that scales with zoom without dithering. The high-resolution PNG (4.7MB) maintains quality at any zoom level.

GraphBmpOpacity — radar overlay blended at 70% opacity over the map.

ManualScaleControlZ — locks the contour color scale to a fixed dBZ range regardless of the actual data range, ensuring consistent colors across different radar files.

CursorValueZ — returns the interpolated dBZ value at the exact mouse position — used for the live tooltip readout.

PeCustomTrackingDataText — custom tooltip formatting showing X km, Y km, and Z dBZ at the cursor.

No XAML designer — Visual Studio has no XAML designer for WinUI 3, in any edition including VS2026, so the chart is declared in markup (<pe:PesgoWinUI x:Name="Pesgo1" />) rather than dragged from the Toolbox. This is a Windows App SDK limitation, not a ProEssentials one.

Chart Loaded, not window Loaded — a WinUI Window is not a Control: it has no Loaded event, no Closing event, and no XAML Height/Width. ProEssentials initialization runs from the chart's own Loaded event, Closing becomes Closed, and SizeAndCenterWindow() sets the window size with a Win32 MoveWindow call.

Pointer events — WPF's MouseMove/MouseEventArgs become WinUI's PointerMoved/PointerRoutedEventArgs, and System.Windows.Point/Rect become Windows.Foundation.Point/Rect. The hover readout body is otherwise unchanged.

• Visual Studio 2026 with the .NET desktop development and Windows application development workloads
• .NET 10 SDK
• Internet connection for NuGet restore
• Python 3 + numpy (only if regenerating the .bin from raw data)

References ProEssentials.Chart.Net10.WinUI. Restore is automatic on build.

The AnyCpu package embeds the native rendering engines inside the assembly and unpacks the one matching the running process at run time, so there is no native DLL to copy or deploy alongside your app. It also carries the control's .pri, whose resources are merged into your app's own .pri at build time.

The nuget.org package is the evaluation build and draws an "Evaluating ProEssentials" watermark across the chart. A licensed installation replaces the assembly and the watermark goes away — everything else behaves identically.

WinUI deploys differently than WPF and WinForms:

• A .NET app is not a single exe — ship the entire build or publish output folder, never a hand-picked subset.
• The target machine needs two runtimes: the .NET 10 Desktop Runtime and the Windows App SDK Runtime. Or publish self-contained with -p:WindowsAppSDKSelfContained=true.
• Your development machine already has both, so it will run from an under-filled folder. Always validate on a clean machine.
• sweep_ref_800x450.bin and radar_background.png are loaded by bare filename at run time, so they must ship beside the exe as well.

• WPF version — wpf-chart-nexrad-radar-reflectivity-proessentials
• Heatmap Spectrogram — Static
• Heatmap Spectrogram — Realtime
• WinUI Starter Template
• All Examples — GigasoftInc on GitHub
• Full Evaluation Download
• gigasoft.com

Radar data courtesy of NOAA National Weather Service. NEXRAD WSR-88D Level II data is free and publicly available from NOAA NCEI and AWS Open Data.

Example code is MIT licensed. ProEssentials requires a commercial license for continued use. NEXRAD data is public domain (NOAA).